MPLS TE TOI
eosborne@cisco.com
Course Number
Presentation_ID
© 2001, Cisco Systems, Inc.
1
Agenda
• How MPLS TE works
• What Code Is MPLS TE In?
• Platform Issues in Implementation
• Lab Demo - config
Presentation_ID
© 2001, Cisco Systems, Inc.
2
How MPLS TE Works
• Prerequisites
• How MPLS-TE Works
• Basic Configuration
• Knobs! Knobs! Knobs!
• Deploying and Designing
Presentation_ID
© 2001, Cisco Systems, Inc.
3
Prerequisites
You should already understand…
• How to configure a Cisco router
• Basic MPLS concepts like push/pop/swap,
EXP, and LFIB
• How a link-state routing protocol works
• Basic QoS mechanisms like MDRR and
LLQ
Presentation_ID
© 2001, Cisco Systems, Inc.
4
Agenda
• Prerequisites
• How MPLS-TE Works
• Basic Configuration
• Knobs! Knobs! Knobs!
• Deploying and Desiginig
Presentation_ID
© 2001, Cisco Systems, Inc.
5
How MPLS-TE Works
• How MPLS-TE Works
-What good is MPLS-TE?
-Information Distribution
-Path Calculation
-Path Setup
-Forwarding Traffic Down A Tunnel
Presentation_ID
© 2001, Cisco Systems, Inc.
6
What Good Is MPLS-TE?
•
There are two kinds of networks
1. Those that have plenty of bandwidth
everywhere
2. Those with congestion in some
places, but not in others
•
Presentation_ID
The first kind always evolve into the
second kind!
© 2001, Cisco Systems, Inc.
7
What Good Is MPLS-TE?
•
MPLS-TE introduces a 3rd kind:
1.
Those that have plenty of bandwidth everywhere
2.
Those with congestion in some places, but not in others
3. Those that use all of their bandwidth
to its maximum efficiency, regardless
of shortest-path routing!
Presentation_ID
© 2001, Cisco Systems, Inc.
8
What Good Is MPLS-TE?
What is MPLS-TE? What is it not?
Multi
Protocol
Label
Switching Traffic
Engineering
Magic
Problem-solving
Labor
Substitute which is
Totally
Effortless
This stuff takes work, but it’s worth it!!!
Presentation_ID
© 2001, Cisco Systems, Inc.
9
Information Distribution
• You need a link-state protocol as
your IGP
IS-IS or OSPF
• Link-state requirement is only for
MPLS-TE!
Not a requirement for VPNs, etc!
Presentation_ID
© 2001, Cisco Systems, Inc.
10
Need for a Link-State Protocol
•
Why do I need a link-state
protocol?
1. To make sure info gets flooded
2. To build a picture of the entire
network
Presentation_ID
© 2001, Cisco Systems, Inc.
11
Need for a Link-State Protocol
Consider the following network:
- All links have a cost of 10
- RtrA’s path to RtrE is A->B->E, cost 20
- All traffic from A to {E,F,G} goes A->B->E
RtrB
RtrF
RtrA
RtrE
RtrG
RtrC
Presentation_ID
© 2001, Cisco Systems, Inc.
RtrD
12
What a DV Protocol Sees
Node Next-Hop
Cost
B
B
10
C
C
10
D
C
20
E
B
20
F
B
30
G
B
30
• RtrA doesn’t see all the
links
• RtrA only knows about
the shortest path
• This is by design
RtrB
RtrF
RtrA
RtrE
RtrG
RtrC
Presentation_ID
© 2001, Cisco Systems, Inc.
RtrD
13
What a LS Protocol Sees
• RtrA sees all links
Node Next-Hop
Cost
B
B
10
C
C
10
D
C
20
E
B
20
F
B
30
G
B
30
• RtrA only computes the
shortest path
• Routing table doesn’t
change
RtrB
RtrF
RtrA
RtrE
RtrG
RtrC
Presentation_ID
© 2001, Cisco Systems, Inc.
RtrD
14
The Problem With Shortest-Path
Node Next-Hop
Cost
B
B
10
C
C
10
D
C
20
E
B
20
F
B
30
G
B
30
• Some links are DS3, some
are OC3
• RtrA has 40Mb of traffic for
RtrF, 40Mb of traffic for RtrG
• Massive (44%) packet loss at
RtrB->RtrE!
• Changing to A->C->D->E
won’t help
RtrB
RtrA
RtrF
OC3
RtrE OC3
DS3
RtrG
OC3
DS3
RtrC
Presentation_ID
© 2001, Cisco Systems, Inc.
DS3
OC3
RtrD
15
What MPLS-TE Addrs
• RtrA sees all links
Node Next-Hop
Cost
B
B
10
C
C
10
D
C
20
E
B
20
F
Tunnel0
30
G
Tunnel1
30
• RtrA computes paths on
properties other than
just shortest cost
• No congestion!
RtrB
RtrA
RtrF
OC3
RtrE OC3
DS3
RtrG
OC3
DS3
RtrC
Presentation_ID
© 2001, Cisco Systems, Inc.
DS3
OC3
RtrD
16
How MPLS-TE Works
• How MPLS-TE Works
-What good is MPLS-TE?
-Information Distribution
-Path Calculation
-Path Setup
-Forwarding Traffic Down A Tunnel
Presentation_ID
© 2001, Cisco Systems, Inc.
17
Information Distribution
• OSPF
-Uses Type 10 (Opaque Area-Local) LSAs
-See draft-katz-yeung-ospf-traffic
Presentation_ID
© 2001, Cisco Systems, Inc.
18
Information Distribution
• IS-IS
-Uses Type 22 TLVs
-See draft-ietf-isis-traffic
Presentation_ID
© 2001, Cisco Systems, Inc.
19
Information Distribution
• IS-IS and OSPF propagate the same
information!
-Link identification
-TE Metric
-Bandwidth info (max physical, max reservable,
available per-class)
-Attribute flags
Presentation_ID
© 2001, Cisco Systems, Inc.
20
Information Distribution
• TE flooding is local to a single
{area|level}
• Inter-{area|level} TE harder, but
possible (think PNNI)
Presentation_ID
© 2001, Cisco Systems, Inc.
21
How MPLS-TE Works
• How MPLS-TE Works
-What good is MPLS-TE?
-Information Distribution
-Path Calculation
-Path Setup
-Forwarding Traffic Down A Tunnel
Presentation_ID
© 2001, Cisco Systems, Inc.
22
Path Calculation
• Modified Dijkstra at tunnel head-end
• Often referred to as CSPF
Constrained SPF
• …or PCALC (path calculation)
Presentation_ID
© 2001, Cisco Systems, Inc.
23
Path Calculation
• Normal SPF – find
shortest path across all
links
“what’s the
shortest path to
all routers?”
• See Perlman (2nd ed),
Moy, etc. for explanation
of SPF
RtrB
RtrF
RtrA
RtrE
RtrG
RtrC
Presentation_ID
© 2001, Cisco Systems, Inc.
RtrD
24
Path Calculation
“what’s the
shortest path to
all routers?”
• Normal SPF – find
shortest path across all
links
• See Perlman (2nd ed),
Moy, etc. for explanation
of SPF
RtrA
Presentation_ID
© 2001, Cisco Systems, Inc.
25
Path Calculation
• Normal SPF – find
shortest path across all
links
“what’s the
shortest path to
all routers?”
• See Perlman (2nd ed),
Moy, etc. for explanation
of SPF
RtrB
RtrA
RtrC
Presentation_ID
© 2001, Cisco Systems, Inc.
26
Path Calculation
• Normal SPF – find
shortest path across all
links
“what’s the
shortest path to
all routers?”
• See Perlman (2nd ed),
Moy, etc. for explanation
of SPF
RtrB
RtrA
RtrC
Presentation_ID
© 2001, Cisco Systems, Inc.
RtrD
27
Path Calculation
• Normal SPF – find
shortest path across all
links
“what’s the
shortest path to
all routers?”
• See Perlman (2nd ed),
Moy, etc. for explanation
of SPF
RtrB
RtrA
RtrE
RtrC
Presentation_ID
© 2001, Cisco Systems, Inc.
RtrD
28
Path Calculation
• Normal SPF – find
shortest path across all
links
“what’s the
shortest path to
all routers?”
• See Perlman (2nd ed),
Moy, etc. for explanation
of SPF
RtrB
RtrF
RtrA
RtrE
RtrG
RtrC
Presentation_ID
© 2001, Cisco Systems, Inc.
RtrD
29
Path Calculation
• Normal SPF – find
shortest path across all
links
“what’s the
shortest path to
all routers?”
• See Perlman (2nd ed),
Moy, etc. for explanation
of SPF
RtrB
RtrF
RtrA
RtrE
RtrG
RtrC
Presentation_ID
© 2001, Cisco Systems, Inc.
RtrD
30
Path Calculation
• Normal SPF – find
shortest path across all
links
“what’s the
shortest path to
all routers?”
• See Perlman (2nd ed),
Moy, etc. for explanation
of SPF
RtrB
RtrF
RtrA
RtrE
RtrG
RtrC
Presentation_ID
© 2001, Cisco Systems, Inc.
RtrD
31
Path Calculation
• Normal SPF – find
shortest path across all
links
“what’s the
shortest path to
all routers?”
• See Perlman (2nd ed),
Moy, etc. for explanation
of SPF
RtrB
RtrF
RtrA
RtrE
RtrG
RtrC
Presentation_ID
© 2001, Cisco Systems, Inc.
RtrD
32
Path Calculation
• Constrained SPF –
find shortest path to
a specific node
“what’s the
shortest path to
router F with
40Mb available??”
• Consider more than
just link cost!
RtrB
RtrA
RtrF
OC3
RtrE OC3
DS3
RtrG
OC3
DS3
RtrC
Presentation_ID
© 2001, Cisco Systems, Inc.
DS3
OC3
RtrD
33
Path Calculation
“what’s the
shortest path to
router F with
40Mb available??”
• Constrained SPF –
find shortest path to
a specific node
• Consider more than
just link cost!
RtrA
Presentation_ID
© 2001, Cisco Systems, Inc.
34
Path Calculation
• Constrained SPF –
find shortest path to
a specific node
“what’s the
shortest path to
router F with
40Mb available??”
• Consider more than
just link cost!
RtrB
RtrA
OC3
OC3
RtrC
Presentation_ID
© 2001, Cisco Systems, Inc.
35
Path Calculation
• Constrained SPF –
find shortest path to
a specific node
“what’s the
shortest path to
router F with
40Mb available??”
• Consider more than
just link cost!
RtrB
RtrA
OC3
OC3
RtrC
Presentation_ID
© 2001, Cisco Systems, Inc.
DS3
RtrD
36
Path Calculation
• Constrained SPF –
find shortest path to
a specific node
“what’s the
shortest path to
router F with
40Mb available??”
• Consider more than
just link cost!
RtrB
RtrA
OC3
RtrE
DS3
OC3
RtrC
Presentation_ID
© 2001, Cisco Systems, Inc.
DS3
RtrD
37
Path Calculation
• Constrained SPF –
find shortest path to
a specific node
“what’s the
shortest path to
router F with
40Mb available??”
• Consider more than
just link cost!
RtrB
RtrA
RtrF
OC3
RtrE OC3
DS3
RtrG
OC3
OC3
RtrC
Presentation_ID
© 2001, Cisco Systems, Inc.
DS3
RtrD
38
Path Calculation
• Constrained SPF –
find shortest path to
a specific node
“what’s the
shortest path to
router F with
40Mb available??”
• Consider more than
just link cost!
RtrB
RtrA
RtrF
OC3
RtrE OC3
DS3
RtrG
OC3
DS3
RtrC
Presentation_ID
© 2001, Cisco Systems, Inc.
DS3
OC3
RtrD
39
Path Calculation
• Constrained SPF –
find shortest path to
a specific node
“what’s the
shortest path to
router F with
40Mb available??”
• Consider more than
just link cost!
RtrB
RtrA
RtrF
OC3
RtrE OC3
DS3
RtrG
OC3
DS3
RtrC
Presentation_ID
© 2001, Cisco Systems, Inc.
DS3
OC3
RtrD
40
Path Calculation
• Constrained SPF –
find shortest path to
a specific node
“what’s the
shortest path to
router F with
40Mb available??”
• Consider more than
just link cost!
RtrB
RtrA
RtrF
OC3
RtrE OC3
DS3
RtrG
OC3
OC3
RtrC
Presentation_ID
© 2001, Cisco Systems, Inc.
DS3
RtrD
41
Path Calculation
• Constrained SPF –
find shortest path to
a specific node
“what’s the
shortest path to
router F with
40Mb available??”
• Consider more than
just link cost!
RtrB
RtrA
RtrF
OC3
RtrE OC3
DS3
OC3
RtrC
Presentation_ID
© 2001, Cisco Systems, Inc.
DS3
RtrD
42
Path Calculation
• Constrained SPF –
find shortest path to
a specific node
“what’s the
shortest path to
router F with
40Mb available??”
• Consider more than
just link cost!
RtrB
RtrA
RtrF
OC3
RtrE OC3
DS3
Presentation_ID
© 2001, Cisco Systems, Inc.
43
Path Calculation
• “But Wait! There’s nothing different
between the two SPF results!”
• ….but….
Presentation_ID
© 2001, Cisco Systems, Inc.
44
Path Calculation
• What about the 2nd
path?
“what’s the
shortest path to
router G with
40Mb available??”
• Available bandwidth
has changed!
RtrB
RtrA
RtrF
OC3
RtrE OC3
5MB
RtrG
OC3
DS3
RtrC
Presentation_ID
© 2001, Cisco Systems, Inc.
DS3
OC3
RtrD
45
Path Calculation
“what’s the
shortest path to
router G with
40Mb available??”
• What about the 2nd
path?
• Available bandwidth
has changed!
RtrA
Presentation_ID
© 2001, Cisco Systems, Inc.
46
Path Calculation
• What about the 2nd
path?
“what’s the
shortest path to
router G with
40Mb available??”
• Available bandwidth
has changed!
RtrB
RtrA
OC3
OC3
RtrC
Presentation_ID
© 2001, Cisco Systems, Inc.
47
Path Calculation
• What about the 2nd
path?
“what’s the
shortest path to
router G with
40Mb available??”
• Available bandwidth
has changed!
RtrB
RtrA
OC3
OC3
RtrC
Presentation_ID
© 2001, Cisco Systems, Inc.
DS3
RtrD
48
Path Calculation
• What about the 2nd
path?
“what’s the
shortest path to
router G with
40Mb available??”
• Available bandwidth
has changed!
RtrB
RtrA
OC3
RtrE
5MB
OC3
RtrC
Presentation_ID
© 2001, Cisco Systems, Inc.
DS3
RtrD
49
Path Calculation
• What about the 2nd
path?
“what’s the
shortest path to
router G with
40Mb available??”
• Available bandwidth
has changed!
RtrB
RtrA
OC3
RtrE
5MB
OC3
RtrC
Presentation_ID
© 2001, Cisco Systems, Inc.
DS3
RtrD
50
Path Calculation
• What about the 2nd
path?
“what’s the
shortest path to
router G with
40Mb available??”
• Available bandwidth
has changed!
RtrB
RtrA
OC3
OC3
RtrC
Presentation_ID
© 2001, Cisco Systems, Inc.
DS3
RtrD
51
Path Calculation
“what’s the
shortest path to
router G with
40Mb available??”
• What about the 2nd
path?
• Available bandwidth
has changed!
RtrA
OC3
RtrC
Presentation_ID
© 2001, Cisco Systems, Inc.
DS3
RtrD
52
Path Calculation
“what’s the
shortest path to
router G with
40Mb available??”
• What about the 2nd
path?
• Available bandwidth
has changed!
RtrA
RtrE
OC3
DS3
RtrC
Presentation_ID
© 2001, Cisco Systems, Inc.
DS3
RtrD
53
Path Calculation
“what’s the
shortest path to
router G with
40Mb available??”
• What about the 2nd
path?
• Available bandwidth
has changed!
RtrF
RtrE OC3
RtrA
RtrG
OC3
DS3
RtrC
Presentation_ID
© 2001, Cisco Systems, Inc.
DS3
OC3
RtrD
54
Path Calculation
“what’s the
shortest path to
router G with
40Mb available??”
• What about the 2nd
path?
• Available bandwidth
has changed!
RtrA
RtrE
RtrG
OC3
DS3
RtrC
Presentation_ID
© 2001, Cisco Systems, Inc.
DS3
OC3
RtrD
55
Path Calculation
Node Next-Hop
Cost
B
B
10
C
C
10
D
C
20
E
B
20
F
Tunnel0
30
G
Tunnel1
30
• End result:
-bandwidth used
efficiently!
RtrB
RtrA
RtrF
OC3
RtrE OC3
DS3
RtrG
OC3
DS3
RtrC
Presentation_ID
© 2001, Cisco Systems, Inc.
DS3
OC3
RtrD
56
Path Calculation
• Happy! Happy!
• Joy! Joy!
Presentation_ID
© 2001, Cisco Systems, Inc.
57
Path Calculation
•
What if there’s more than one path that
meets the minimum requirements (BW,
etc)?
•
PCALC algorithm:
1. find all paths with the lowest IGP cost
2. then pick the path with the highest
minimum bandwidth along the path
3. then pick the path with the lowest hop
count (not IGP cost, just hop count)
4. then just pick one path at random
Presentation_ID
© 2001, Cisco Systems, Inc.
58
Path Calculation
What’s the best
path from A to Z
with BW of 20M?
{cost,available BW}
Path has cost of
25, not the
lowest cost!
{10,100M}
{8,80M}
RtrA
RtrZ
{4,90M}
{8,90M}
all left-side links
are {10,100M}
Presentation_ID
© 2001, Cisco Systems, Inc.
{8,90M}
all right-side links
are {5,50M}
59
Path Calculation
What’s the best
path from A to Z
with BW of 20M?
{cost,available BW}
Path min BW is
lower than the
other paths!
{8,80M}
RtrA
RtrZ
{4,90M}
{8,90M}
all left-side links
are {10,100M}
Presentation_ID
© 2001, Cisco Systems, Inc.
{8,90M}
all right-side links
are {5,50M}
60
Path Calculation
What’s the best
path from A to Z
with BW of 20M?
{cost,available BW}
RtrA
Hop count is 5,
other paths are
4!
RtrZ
{4,90M}
{8,90M}
all left-side links
are {10,100M}
Presentation_ID
© 2001, Cisco Systems, Inc.
{8,90M}
all right-side links
are {5,50M}
61
Path Calculation
What’s the best
path from A to Z
with BW of 20M?
{cost,available BW}
RtrA
Pick a path at
random!
RtrZ
{8,90M}
all left-side links
are {10,100M}
Presentation_ID
© 2001, Cisco Systems, Inc.
{8,90M}
all right-side links
are {5,50M}
62
Path Calculation
What’s the best
path from A to Z
with BW of 20M?
{cost,available BW}
RtrA
RtrZ
{8,90M}
all left-side links
are {10,100M}
Presentation_ID
© 2001, Cisco Systems, Inc.
all right-side links
are {5,50M}
63
How MPLS-TE Works
• How MPLS-TE Works
-What good is MPLS-TE?
-Information Distribution
-Path Calculation
-Path Setup
-Forwarding Traffic Down A Tunnel
Presentation_ID
© 2001, Cisco Systems, Inc.
64
Path Setup
• Cisco MPLS-TE uses RSVP
• RFC2205, plus draft-ietf-mpls-rsvplsp-tunnel
Presentation_ID
© 2001, Cisco Systems, Inc.
65
Path Setup
• Once the path is calculated, it is
handed to RSVP
• RSVP uses PATH and RESV
messages to request an LSP along
the calculated path
Presentation_ID
© 2001, Cisco Systems, Inc.
66
Path Setup
• PATH message: “Can I have 40Mb along this path?”
• RESV message: “Yes, and here’s the label to use.”
• LFIB is set up along each hop
= PATH messages
= RESV messages
RtrB
RtrF
RtrA
RtrE
RtrG
RtrC
Presentation_ID
© 2001, Cisco Systems, Inc.
RtrD
67
Path Setup
• Errors along the way will trigger
RSVP errors
• May also trigger re-flooding of TE
info if appropriate
Presentation_ID
© 2001, Cisco Systems, Inc.
68
How MPLS-TE Works
• How MPLS-TE Works
-What good is MPLS-TE?
-Information Distribution
-Path Calculation
-Path Setup
-Forwarding Traffic Down A Tunnel
Presentation_ID
© 2001, Cisco Systems, Inc.
69
Forwarding Traffic Down a Tunnel
• There are three ways traffic can be
forwarded down a TE tunnel
-Autoroute
-Static routes
-Policy routing
• For the first two, MPLS-TE gets you
unequal-cost load-balancing.
Presentation_ID
© 2001, Cisco Systems, Inc.
70
Autoroute
• Autoroute = “use the tunnel as a
directly connected link for SPF
purposes”
• This is not the CSPF (for path
determination), but the regular IGP
SPF (route determination)
• Behavior is intuitive, operation can
be confusing
Presentation_ID
© 2001, Cisco Systems, Inc.
71
Autoroute
This is the physical topology
RtrB
RtrF
RtrA
RtrH
RtrE
RtrG
RtrI
RtrC
Presentation_ID
© 2001, Cisco Systems, Inc.
RtrD
72
Autoroute
This is RtrA’s logical topology
Other routers don’t see the tunnel!
RtrB
RtrF
RtrA
RtrH
RtrE
RtrG
Tunnel1
RtrI
RtrC
Presentation_ID
© 2001, Cisco Systems, Inc.
RtrD
73
Autoroute
Node Next-Hop
Cost
B
B
10
C
C
10
D
C
20
E
B
20
F
B
30
G
Tunnel1
30
H
Tunnel1
40
I
Tunnel1
40
Router A’s routing table,
built via autoroute.
Everything “behind” the
tunnel is routed via the
tunnel.
RtrB
RtrF
RtrA
RtrH
RtrE
RtrG
Tunnel1
RtrI
RtrC
Presentation_ID
© 2001, Cisco Systems, Inc.
RtrD
74
Static routing
RtrA(config)#ip route H.H.H.H
255.255.255.255 Tunnel1
RtrB
RtrF
RtrA
RtrH
RtrE
RtrG
Tunnel1
RtrI
RtrC
Presentation_ID
© 2001, Cisco Systems, Inc.
RtrD
75
Static routing
Node Next-Hop
Cost
B
B
10
C
C
10
D
C
20
E
B
20
F
B
30
G
B
30
H
Tunnel1
40
I
B
40
RtrH is known via the
tunnel.
RtrG is not routed to over
the tunnel, even though
it’s the tunnel tail!
RtrB
RtrF
RtrA
RtrH
RtrE
RtrG
Tunnel1
RtrI
RtrC
Presentation_ID
© 2001, Cisco Systems, Inc.
RtrD
76
Unequal-Cost Load Balancing
• IP routing has equal-cost loadbalancing, but not unequal-cost*
• Unequal-cost load balancing difficult
to do while guaranteeing a loop-free
topology
*EIGRP has ‘variance’, but that’s not as flexible, and besides, MPLS-TE and EIGRP
are two different things
Presentation_ID
© 2001, Cisco Systems, Inc.
77
Unequal-Cost Load Balancing
• Since MPLS doesn’t forward based
on IP header, permanent routing
loops don’t happen.
• 16 hash buckets for next-hop, shared
in rough proportion to tunnel BW
Presentation_ID
© 2001, Cisco Systems, Inc.
78
Unequal-cost, Example 1
RtrF
RtrA
40MB
20MB
RtrE
RtrG
gsr1#show ip route 192.168.1.8
Routing entry for 192.168.1.8/32
Known via "isis", distance 115, metric 83, type level-2
Redistributing via isis
Last update from 192.168.1.8 on Tunnel0, 00:00:21 ago
Routing Descriptor Blocks:
* 192.168.1.8, from 192.168.1.8, via Tunnel0
Route metric is 83, traffic share count is 2
192.168.1.8, from 192.168.1.8, via Tunnel1
Route metric is 83, traffic share count is 1
Presentation_ID
© 2001, Cisco Systems, Inc.
79
Unequal-cost, Example 1
RtrF
RtrA
40MB
20MB
RtrE
RtrG
gsr1#sh ip cef 192.168.1.8 int
………
Load distribution: 0 1 0 1 0 1 0 1 0 1 0 0 0 0 0 0 (refcount 1)
Hash OK Interface
Address
Packets Tags imposed
1
Y
Tunnel0
point2point
0
{23}
2
Y
Tunnel1
point2point
0
{34}
………
Note that the load distribution is 11:5 – very close to
2:1, but not quite!
Presentation_ID
© 2001, Cisco Systems, Inc.
80
Unequal-cost, Example 2
RtrF
RtrA
100MB
10MB
1MB
RtrE
RtrG
gsr1#sh ip rou 192.168.1.8
Routing entry for 192.168.1.8/32
Known via "isis", distance 115, metric 83, type level-2
Redistributing via isis
Last update from 192.168.1.8 on Tunnel2, 00:00:08 ago
Routing Descriptor Blocks:
* 192.168.1.8, from 192.168.1.8, via Tunnel0
Route metric is 83, traffic share count is 100
192.168.1.8, from 192.168.1.8, via Tunnel1
Route metric is 83, traffic share count is 10
192.168.1.8, from 192.168.1.8, via Tunnel2
Route metric is 83, traffic share count is 1
Q:How does 100:10:1 fit into a 16-deep bucket?
Presentation_ID
© 2001, Cisco Systems, Inc.
81
Unequal-cost, Example 2
RtrF
RtrA
100MB
10MB
1MB
RtrE
RtrG
gsr1#sh ip cef 192.168.1.8 internal
………
Load distribution: 0 1 0 0 0 0 0 0 0 0 0 0 0 0 0 0 (refcount 1)
Hash
1
2
………
OK
Y
Y
Interface
Tunnel0
Tunnel1
Address
point2point
point2point
Packets
0
0
Tags imposed
{36}
{37}
A:Any way it wants to! 15:1, 14:2, 13:2:1, it depends on
the order the tunnels come up.
Deployment guideline: don’t use tunnel metrics that don’t reduce to
16 buckets!
Presentation_ID
© 2001, Cisco Systems, Inc.
82
Policy routing
RtrA(config-if)#ip policy route-map set-tunnel
RtrA(config)#route-map set-tunnel
RtrA(config-route-map)#match ip address 101
RtrA(config-route-map)#set interface Tunnel1
RtrB
RtrF
RtrA
RtrH
RtrE
RtrG
Tunnel1
RtrI
RtrC
Presentation_ID
© 2001, Cisco Systems, Inc.
RtrD
83
Policy routing
Node Next-Hop
Cost
B
B
10
C
C
10
D
C
20
E
B
20
F
B
30
G
B
30
H
B
40
I
B
40
Routing table isn’t
affected by policy
routing.
Need (12.0(16)ST or 12.2T)
or higher for ‘set int
Tunnel’ to work
(CSCdp54178)
RtrB
RtrF
RtrA
RtrH
RtrE
RtrG
Tunnel1
RtrI
RtrC
Presentation_ID
© 2001, Cisco Systems, Inc.
RtrD
84
Forwarding Traffic Down a Tunnel
• You can use any combination of
autoroute, static routes, or PBR.
• …but simple is better unless you have a
good reason.
• Recommendation: either autoroute or
statics to BGP next-hops, depending on
your needs.
Presentation_ID
© 2001, Cisco Systems, Inc.
85
Agenda
• Prerequisites
• How MPLS-TE Works
• Basic Configuration
• Knobs! Knobs! Knobs!
• Deploying and Desiginig
Presentation_ID
© 2001, Cisco Systems, Inc.
86
Basic Configuration
• Basic Configuration
-Basic Midpoint/Tail Config
-Basic Headend Config
-Path-option
-Bandwidth
Presentation_ID
© 2001, Cisco Systems, Inc.
87
Basic Midpoint/Tail Config
(globally)
ip cef {distributed}
mpls traffic-eng tunnels
Presentation_ID
© 2001, Cisco Systems, Inc.
88
Basic Midpoint/Tail Config
(per interface)
mpls traffic-eng tunnels
Presentation_ID
© 2001, Cisco Systems, Inc.
89
Basic Midpoint/Tail Config
(if IGP == OSPF)
router ospf <x>
mpls traffic-eng router-id
Loopback0
mpls traffic-eng area <y>
Presentation_ID
© 2001, Cisco Systems, Inc.
90
Basic Midpoint/Tail Config
(if IGP == OSPF)
• MPLS TE is a single area only
(usually area 0)
• RID must be set (unlike OSPF RID)
It’s a Very Very Good idea to make it a
/32 loopback.
Presentation_ID
© 2001, Cisco Systems, Inc.
91
Basic Midpoint/Tail Config
(if IGP == IS-IS)
router isis <x>
mpls traffic-eng router-id
Loopback0
mpls traffic-eng level-{1,2}
metric-style wide
Presentation_ID
© 2001, Cisco Systems, Inc.
92
Basic Midpoint/Tail Config
(if IGP == IS-IS)
• MPLS TE is a single level only
• RID must be set (unlike OSPF RID)
It’s a Very Very Good idea to make it a
/32 loopback.
Presentation_ID
© 2001, Cisco Systems, Inc.
93
Basic Midpoint/Tail Config
‘metric-style wide’ - ???
• IS-IS must have wide metrics enabled
• This is discussed in more detail later
in this presentation; see also
www.cisco.com.
Presentation_ID
© 2001, Cisco Systems, Inc.
94
Basic Midpoint/Tail Config
• Total config tally so far:
1 line globally
1 line per interface
2 lines if OSPF
3 lines if IS-IS
Presentation_ID
© 2001, Cisco Systems, Inc.
95
Basic Headend Config
• Headend needs the 4-5 ‘mid/tail’ lines
• But wait – there’s more!
Presentation_ID
© 2001, Cisco Systems, Inc.
96
Basic Headend Config
• Create the tunnel interface
interface Tunnel0
ip unnumbered Loopback0
tunnel mode mpls traffic-eng
unnumbered to Loop0
tunnel source Loopback0
tunnel destination <tunnel endpoint>
tunnel mpls traffic-eng autoroute
tunnel mpls traffic-eng path-option 10 dynamic
path-option tells the tunnel how to get to tail
’10’ is the priority of the path-option
there are other options besides dynamic
autoroute is not strictly necessary, but is useful
Presentation_ID
© 2001, Cisco Systems, Inc.
97
Basic Headend Config
• Total config tally:
1 line globally
1 line per interface
2 lines if OSPF
3 lines if IS-IS
7 lines per tunnel at headend
Presentation_ID
© 2001, Cisco Systems, Inc.
98
Agenda
• Prerequisites
• How MPLS-TE Works
• Basic Configuration
• Knobs! Knobs! Knobs!
• Deploying and Desiginig
Presentation_ID
© 2001, Cisco Systems, Inc.
99
Knobs! Knobs! Knobs!
•
Influencing the Path Selection
•
Auto-Bandwidth
•
Fast Reroute
•
DiffServ-Aware Traffic Engineering
Presentation_ID
© 2001, Cisco Systems, Inc.
100
Knobs! Knobs! Knobs!
•
Influencing the Path Selection
Bandwidth
Priority
Administrative Weight
Attributes & Affinity
Presentation_ID
© 2001, Cisco Systems, Inc.
101
Bandwidth
ip rsvp bandwidth <x> <y>
• Per-physical-interface command
• X = amount of reservable BW, in K
• Y = not used by MPLS-TE
• default: X==Y==75% of link bandwidth
Presentation_ID
© 2001, Cisco Systems, Inc.
102
Priority
tunnel mpls traffic-eng <S> {H}
• Configured on tunnel inteface
• S = setup priority (0-7)
• H = holding priority (0-7)
• lower number is more important, or better.
Presentation_ID
© 2001, Cisco Systems, Inc.
103
Priority
• New tunnel with better setup priority
will force teardown of alreadyestablished tunnel with worse
holding priority
• Configuring S<H is illegal
• Default is S=7,H=7
Presentation_ID
© 2001, Cisco Systems, Inc.
104
Priority
= 40MB tunnel with S=7, H=7
= 40MB tunnel with S=6, H=6
RtrA
45MB
RtrC
RtrB
Presentation_ID
© 2001, Cisco Systems, Inc.
45MB
RtrD
45MB
105
Priority
= 40MB tunnel with S=7, H=7
= 40MB tunnel with S=6, H=6
RtrA
45MB
RtrC
ResvTear
RtrB
45MB
RtrD
45MB
• RtrC sends ResvTear to RtrA, tunnel is
torn down.
Presentation_ID
© 2001, Cisco Systems, Inc.
106
Priority
“Should I ever set S != H?”
No. Not unless you know you
have a good reason to.
Presentation_ID
© 2001, Cisco Systems, Inc.
107
Administrative Weight
mpls traffic-eng
administrative-weight <X>
• Per-physical-interface command
• X = 0-(232 –1)
• gives a metric that be considered for use
instead of the IGP metric
• this can be used as a per-tunnel delaysensitive metric for doing VoIP TE
Presentation_ID
© 2001, Cisco Systems, Inc.
108
Administrative Weight
tunnel mpls traffic-eng pathselection metric {te|igp}
• Per-tunnel command
• default is ‘igp’
• ‘te’ uses the configured administrativeweight to determine shortest cost
• use this as a delay-sensitve metric
Presentation_ID
© 2001, Cisco Systems, Inc.
109
Delay-Sensitve Metric with
Adminastrative Weight
tunnel mpls traffic-eng pathselection metric {te|igp}
mpls traffic-eng administrativeweight <x>
• configure admin weight == interface delay
• configure VoIP tunnels to use TE metric to
calculate the path
• delay-sensitive metric!
Presentation_ID
© 2001, Cisco Systems, Inc.
110
Attributes & Affinity
• Link attribute – 32 separate link
properties
• Tunnel affinity – desire for links to
have certain properties set
• Invent your own property meanings
Presentation_ID
© 2001, Cisco Systems, Inc.
111
Administrative Weight
mpls traffic-eng attributeflags <0x0-0xFFFFFFFF>
• Per-physical-interface command
Presentation_ID
© 2001, Cisco Systems, Inc.
112
Administrative Weight
tunnel mpls traffic-eng
affinity <0x0-0xFFFFFFFF>
{mask <0x0-0xFFFFFFFF>}
• Per-tunnel command
• Mask is a collection of do-care bits
• ‘affinity 0x2 mask 0xA’ means ‘I care about
bits 2 and 8; bit 2 must be set, bit 8 must
be 0’
Presentation_ID
© 2001, Cisco Systems, Inc.
113
Administrative Weight
• Q: How should I use admin-weight?
• A: To exclude some links from
consideration by some tunnels
• …so give a satellite link an attribute
of 0x2, and any VoIP tunnels can be
configured with ‘affinity 0x0
mask 0x2’
Presentation_ID
© 2001, Cisco Systems, Inc.
114
Knobs! Knobs! Knobs!
•
Influencing the Path Selection
•
Auto-Bandwidth
•
Fast Reroute
•
DiffServ-Aware Traffic Engineering
Presentation_ID
© 2001, Cisco Systems, Inc.
115
Auto-Bandwidth
tunnel mpls traffic-eng auto-bw ?
collect-bw Just collect Bandwidth info on this tunnel
frequency Frequency to change tunnel BW
max-bw
Set the Maximum Bandwidth for auto-bw on this tunnel
min-bw
Set the Minimum Bandwidth for auto-bw on this tunnel
<cr>
• Per-tunnel command
• Periodically changes tunnel BW
reservation based on traffic out tunnel
• Timers are tunable to make auto-bw more
or less sensitive
Presentation_ID
© 2001, Cisco Systems, Inc.
116
Auto-Bandwidth
tunnel mpls traffic-eng auto-bw ?
collect-bw Just collect Bandwidth info on this tunnel
frequency Frequency to change tunnel BW
max-bw
Set the Maximum Bandwidth for auto-bw on this tunnel
min-bw
Set the Minimum Bandwidth for auto-bw on this tunnel
<cr>
• Per-tunnel command
• Periodically changes tunnel BW
reservation based on traffic out tunnel
• Timers are tunable to make auto-bw more
or less sensitive
tradeoff: quicker reaction vs. more churn
Presentation_ID
© 2001, Cisco Systems, Inc.
117
Auto-Bandwidth
gsr1#sh mpls traffic-eng tunnels t0
…
Config Parameters:
…
auto-bw: (86400/86259) 0 Bandwidth Requested: 100
• 86400 = reoptimization time (default 24h)
tunnel mpls traffic-eng auto-bw frequency <x>
• 86259 = time left to reoptimization
• 0 = BW measured at end of last reopt interval
• bw requested = signalled tunnel BW
tunnel mpls traffic-eng {max-bw|min-bw} <bw>
Presentation_ID
© 2001, Cisco Systems, Inc.
118
Knobs! Knobs! Knobs!
•
Influencing the Path Selection
•
Auto-Bandwidth
•
Fast Reroute
•
DiffServ-Aware Traffic Engineering
Presentation_ID
© 2001, Cisco Systems, Inc.
119
Fast Reroute
• In an IP network, a link failure causes
several seconds of outage
Thing
Dependency Time
Link failure
detection
Media- and platformspecific
~usecs (POS + APS)
Info propagation
IGP timers, network
~5-30sec
size, collective router
load
Route recalculation LSDB size, CPU load ~1-2sec
Presentation_ID
© 2001, Cisco Systems, Inc.
120
Fast Reroute
• In an MPLS network, there’s more work to
be done, so a (slightly) longer outage
happens
Thing
Dependency Time
Link failure
detection
Media- and platformspecific
~usecs (POS + APS)
Info propagation
IGP timers, network
~5-30sec
size, collective router
load
Route recalculation LSDB size, CPU load ~1-2sec
New LSP setup
network size, CPU
~5-10sec
load
Presentation_ID
© 2001, Cisco Systems, Inc.
121
Three Kinds of FRR
• Link Protection
the only scheme implemented today
• Node Protection
on the way
• Path Protection
on development radar
Presentation_ID
© 2001, Cisco Systems, Inc.
122
Link Protection
• TE tunnel A->B->D->E
RtrA
RtrB
RtrD
RtrE
RtrC
Presentation_ID
© 2001, Cisco Systems, Inc.
123
Link Protection
• B has a pre-provisioned backup tunnel to the
other end of the protected link (RtrD)
• B relies on the fact that D is using global label
space
RtrA
RtrB
RtrD
RtrE
RtrC
Presentation_ID
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124
Link Protection
• B->D link fails, A->E tunnel is encapsulated in B>D tunnel
• Backup tunnel is used until A can recompute
tunel path as A->B->C->D->E (so 10-30sec or so)
RtrA
RtrB
RtrD
RtrE
RtrC
Presentation_ID
© 2001, Cisco Systems, Inc.
125
Link Protection
• On tunnel headend:
tunnel mpls traffic-eng fast-reroute
RtrA
RtrB
RtrD
RtrE
RtrC
• On protected link:
mpls traffic-eng backup-path <backup-tunnel>
Presentation_ID
© 2001, Cisco Systems, Inc.
126
Node Protection
•RtrA has a tunnel A->B->D->E->F
•RtrB has a protect tunnel B->C->E->D
RtrA
RtrB
RtrD
RtrE
RtrF
RtrC
Presentation_ID
© 2001, Cisco Systems, Inc.
127
Node Protection
• Link protection is OK if the B->D link
goes down
• What if Router D goes away?
RtrA
RtrB
RtrD
RtrE
RtrF
RtrC
Presentation_ID
© 2001, Cisco Systems, Inc.
128
Node Protection
• Solution: protect tunnel to the hop
past the protected link
RtrA
RtrB
RtrD
RtrE
RtrF
RtrC
Presentation_ID
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129
Node Protection
• Node protection still has the same
convergence properties as link protection
• Deciding where to place your backup tunnels
is a much harder to problem to solve largescale
…turns out it’s an NP-complete problem.
• For small-scale protection, link may be better
• Cisco is developing tools to solve these hard
problems for you (see TunnelVision, later)
Presentation_ID
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130
Path Protection
• Path Protection: multiple tunnels from TE
head to tail, across diverse paths
RtrA
RtrB
RtrD
RtrE
RtrF
RtrC
Presentation_ID
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131
Path Protection
•
Path Protection: least scalable, most
resource-consuming, slowest
convergence of all 3 protection schemes
•
Path protection is useful in two places:
1) when you have more links than tunnels
2) when you need to protect links not using
global label space
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Path vs. Local Protection
Local (link/node) Protection
Thing
Dependency
Time
Link failure detection
Media- and platformspecific
~usecs (POS + APS)
Local switchover to
protect tunnel
RP->IPC communication
time
~few msec or less
Path Protection
Thing
Dependency
Time
Link failure detection
Media- and platformspecific
~usecs (POS + APS)
Info propagation
IGP timers, network size,
collective router load
~5-30sec
Headend switchover to
protect LSP
network size, CPU load
~msec
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Path vs. Local Protection
How Many Backup Tunels Are Required?
• consider 3 LSPs: A->J, B->J, C->
• how can we protect against a failure of RtrF?
RtrA
RtrB
RtrD
RtrE
RtrC
Presentation_ID
RtrF
© 2001, Cisco Systems, Inc.
RtrG
RtrI
RtrJ
RtrH
134
Path vs. Local Protection
Number of Backup Tunnels Required
Protection Scheme
1 tunnel per…
Link protection
Protected link (since all protected links are p2p)
Protecting the D->F link
Protect LSP carries 2 LSPs inside it
RtrA
= protecting B,G
RtrB
RtrD
RtrE
RtrC
Presentation_ID
RtrF
© 2001, Cisco Systems, Inc.
RtrG
RtrI
RtrJ
RtrH
135
Path vs. Local Protection
Number of Backup Tunnels Required
Protection Scheme
1 tunnel per…
Node protection
Next-next-hop
Protecting Router F
= protecting R
RtrA
RtrB
= protecting B,G
RtrD
RtrE
RtrC
Presentation_ID
RtrF
© 2001, Cisco Systems, Inc.
RtrG
RtrI
RtrJ
RtrH
136
Path vs. Local Protection
Number of Backup Tunnels Required
Protection Scheme
1 tunnel per…
Path protection
LSP
Protecting Each LSP
R and R’ have mutually exlusive reservations!
RtrA
RtrB
RtrD
RtrE
RtrC
Presentation_ID
RtrF
© 2001, Cisco Systems, Inc.
RtrG
RtrI
RtrJ
RtrH
137
Path vs. Local Protection
Number of Backup Tunnels Required
Protection Scheme
1 tunnel per…
Link protection
Protected link (since all protected links are p2p)
Node protection
Next-next-hop
Path protection
LSP
• So is Path Protection evil?
No. But it has some scalability limits.
Presentation_ID
© 2001, Cisco Systems, Inc.
138
Knobs! Knobs! Knobs!
•
Influencing the Path Selection
•
Auto-Bandwidth
•
Fast Reroute
•
DiffServ-Aware Traffic Engineering
Presentation_ID
© 2001, Cisco Systems, Inc.
139
Diffserv-Aware Traffic
Engineering
• MPLS can advertise and reserve
bandwidth on a link
• Works great, but what if you send a
mix of LLQ and BE traffic down a TE
tunnel?
• Need some way to differentiate and
reserve LLQ bandwidth on a link.
Presentation_ID
© 2001, Cisco Systems, Inc.
140
Diffserv-Aware Traffic
Engineering
RtrA
RtrE
RtrC
RtrG
RtrB
RtrD
RtrF
• 2 tunnels across C<->E link
• 40MB each tunnel
• 100MB reservable on C<->E, with a 30MB LLQ
• What happens when both tunnels send 20MB of VoIP
traffic?
Presentation_ID
© 2001, Cisco Systems, Inc.
141
Diffserv-Aware Traffic
Engineering
RtrA
30MB LLQ+40MB LLQ traffic = 10MB not LLQ’d!
RtrE
RtrC
RtrG
RtrB
RtrD
RtrF
• Problem: only one pool on an interface, no
way to differentiate what types of traffic are
carried!
• Solution: advertise more than one pool!
Presentation_ID
© 2001, Cisco Systems, Inc.
142
Diffserv-Aware Traffic
Engineering
ip rsvp bandwidth <x> sub-pool <y>
• ‘this link has available bandwidth of X, Y of
which is in a sub-pool’
• Not quite two pools, really – no sense in
witholding bandwidth from global availabilty
if it’s not in use
• …which means sub-pool tunnels need to
have a better priority than non-sub-pool
tunnels.
Presentation_ID
© 2001, Cisco Systems, Inc.
143
Diffserv-Aware Traffic
Engineering
tunnel mpls traffic-eng bandwidth <x>
sub-pool
• ‘this tunnel wants to reserve X Kbps from a
sub-pool’
• sub-pool BW is looked at instead of global
pool BW
• if sub-pool BW is not available, tunnel won’t
come up
Presentation_ID
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144
Agenda
• Prerequisites
• How MPLS-TE Works
• Basic Configuration
• Knobs! Knobs! Knobs!
• Deploying and Designing
Presentation_ID
© 2001, Cisco Systems, Inc.
145
Deploying and Designing
• Deployment Methodologies
• Scalability
• Management
• Security
Presentation_ID
© 2001, Cisco Systems, Inc.
146
Deployment Methodologies
• Two ways to deploy MPLS-TE
-as needed to clear up congestion
-full mesh between a set of routers
• Both methods are valid, both have
their pros and cons
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147
As Needed
• Case study: a large US ISP
RtrA
RtrC
RtrB
•All links are OC12
•A has consistent 700MB to send to C
•~100MB constantly dropped!
RtrD
Presentation_ID
© 2001, Cisco Systems, Inc.
RtrE
148
As Needed
• Solution: multiple tunnels, unequal-cost
load sharing!
RtrA
RtrC
RtrB
•Tunnels with bandwidth in 3:1 ratio
•175MB sent the long way
•525MB sent the short way
•No out-of-order packet issues –
CEF’s normal per-flow hashing is used!
RtrD
Presentation_ID
© 2001, Cisco Systems, Inc.
RtrE
149
As Needed
• From RtrA’s perspective, topo is:
RtrA
RtrC
RtrB
RtrD
Presentation_ID
© 2001, Cisco Systems, Inc.
RtrE
150
As Needed
• As Needed: easy, quick, but hard to track
over time.
• Easy to forget why a tunnel is in place
• Inter-node BW requirements may change,
tunnels may be working around issues
that no longer exist
• Link protection pretty straightforward,
node protection much harder to track
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151
Full Mesh
• Put a full mesh of TE tunnels between
routers
• Initially deploy tunnels with 0 BW
• Watch Tunnel inteface stats, see how
much BW you are using between router
pairs
-Tunnels are intefaces – use IF-MIB!
-Make sure that tunnel bw <= network bw
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152
Full Mesh
• Some folks deploy full mesh just to
get router-to-router (pop-to-pop)
traffic matrix
• Largest TE network ~80 routers full
mesh (~6400 tunnels)
• As tunnel BW is changed, tunnels
will find the best path across your
network
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153
Full Mesh
• Physical topology is:
RtrA
RtrC
RtrB
RtrD
Presentation_ID
© 2001, Cisco Systems, Inc.
RtrE
154
Full Mesh
• Logical topology is:
RtrA
RtrC
RtrB
RtrD
Presentation_ID
© 2001, Cisco Systems, Inc.
RtrE
155
Full Mesh
• Things to remember with full mesh
-N routers, N*(N-1) tunnels
-Routing protocols not run over TE
tunnels – unlike an ATM full mesh!
-Tunnels are unidirectional – this is a
Good Thing
…can have different BW reservations in two different directions
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156
Full Mesh
• Best practices for full mesh:
-periodically reoptimize tunnels based
on need (just like an ATM network)
-TE was always designed to be a
combination of online (router-based) and
offline (NMS) calculation
-Node protection more practical in a fullmesh, offline-generate TE topo
Presentation_ID
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157
Deploying and Designing
• Deployment Methodologies
• Scalability
• Management
• Security
Presentation_ID
© 2001, Cisco Systems, Inc.
158
Scalability
• How many tunnels on a router?
Code
# headend
tunnels
12.0S 300
12.0ST 600
# of
midpoints
10,000
10,000
• Tests were done on a GSR.
• RSP4, RSP8, VXR300, VXR400 will be
similar
Presentation_ID
© 2001, Cisco Systems, Inc.
159
Scalability
• 300 headends = ~90,000 tunnels
• 600 headends = ~360,000 tunnels
• Largest TE network today = ~6400 tunnels
• 90,000 tunnels = 6400*14
• 360,000 tunnels = 6400*56
• There are other factors to consider
-IGP scaling, BGP, etc
• …but MPLS-TE is not the gating factor in
network scaling!
Presentation_ID
© 2001, Cisco Systems, Inc.
160
Scalability
• Largest TE network today = ~6400 tunnels
• 80 routers, ~6400 tunnels full mesh
• 12.0S scales to 300 headends, ~90,000 tunnels full
mesh
• 12.0ST – 600 headends, 360,000 tunnels full mesh
• 300=80*3.75
..or (90,000=6400*14) if you’re in marketing
• 600=80*7.50
… or (360,000=6400*56)
• Bottom line: MPLS-TE is not a gating factor in
network scaling!
Presentation_ID
© 2001, Cisco Systems, Inc.
161
Scalability
http://www.cisco.com/univercd/cc/td/d
oc/product/software/ios120/120newft/
120limit/120st/120st14/scalable.htm
…or just search CCO for “Scalability
Enhancements for MPLS Traffic
Engineering”
Presentation_ID
© 2001, Cisco Systems, Inc.
162
Deploying and Designing
• Deployment Methodologies
• Combining VPN+TE
• Scalability
• Management
• Security
Presentation_ID
© 2001, Cisco Systems, Inc.
163
Traffic Engineering MIBs
• Interfaces MIB
• MPLS-TE-MIB
• CISCO-TE-MIB
• MPLS-DS-TE-MIB
Presentation_ID
© 2001, Cisco Systems, Inc.
164
MPLS-TE-MIB
• Goal: Exposes MPLS TE tunnels
Configured tunnel heads and path(s)
Active path(s)
Back-up/stand-by path(s)
Traps
Presentation_ID
© 2001, Cisco Systems, Inc.
165
MPLS-DS-TE-MIB
• Goal: Exposes DiffServ-Aware Traffic
Engineering parameters.
• Extends the MPLS-TE-MIB and MPLS-LSRMIBs.
• Work still in progress: presented version
00 in Minneapolis IETF meeting (March
2001).
Presentation_ID
© 2001, Cisco Systems, Inc.
166
Cisco-TE-MIB
• Exposes non-standardized TE
features such as additional CSPF
extensions, auto-bandwidth tunnels,
link/node protection, path options,
etc…, etc….
• Other vendors have similar
proprietary MIBs.
Presentation_ID
© 2001, Cisco Systems, Inc.
167
TunnelVision
• Need a tool to help manage TE LSPs?
• TunnelVision (server and client
component, will run on Solaris and
Win2k)
• Not a network modeling tool!
Use WANDL, Orchestream, MakeSys,
Opnet, others
Presentation_ID
© 2001, Cisco Systems, Inc.
168
TunnelVision Architecture
Control
Data
Browser
http
Web Server
TV
Applet
TV Server
Application
Commands
Presentation_ID
© 2001, Cisco Systems, Inc.
Solaris
WorkStation
Telnet
SNMP
169
TunnelVision Client Screenshot
Presentation_ID
© 2001, Cisco Systems, Inc.
170
TunnelVision
• Cisco is also working with an
external partner to add node
protection path calculation
• The partner has world-class
algorithm development experience
• TunnelVision will feed topology to
this tool, tool will calculate backup
paths
Presentation_ID
© 2001, Cisco Systems, Inc.
171
Other Tools
• There are other MPLS-TE tools
WANDL, Make Systems, Orchestream,
OpNet, etc.
• Off-net modeling and path calculation
very important to help scale TE
deployment
Presentation_ID
© 2001, Cisco Systems, Inc.
172
Deploying and Designing
• Deployment Methodologies
• Scalability
• Management
• Security
Presentation_ID
© 2001, Cisco Systems, Inc.
173
Security
• MPLS-TE is not enabled on externally
facing intefaces
• Biggest security risk is spoofed
RSVP
-hacker would have to know a lot about
your topo to do anything
-RSVP authentication exists (rfc2747),
not implemented
Presentation_ID
© 2001, Cisco Systems, Inc.
174
Security
• MPLS-TE can hide your network
topology from the outside world
• Is this “security”? That’s debatable.
But it’s certainly a neat knob!
RtrA(config)#no mpls ip propagate-ttl ?
forwarded Propagate IP TTL for forwarded traffic
local
Presentation_ID
Propagate IP TTL for locally originated traffic
© 2001, Cisco Systems, Inc.
175
Conclusion
• TE is cool
• You should use lots of it
• It will make you popular
• It also cures leprosy, rickets, and
tennis elbow!
Presentation_ID
© 2001, Cisco Systems, Inc.
176
Agenda
• How MPLS TE works
• What Code Is MPLS TE In?
• Platform Issues in Implementation
• Lab Demo - config
Presentation_ID
© 2001, Cisco Systems, Inc.
177
What Code Is MPLS-TE In?
• IS-IS Support: 12.0(5)S, 12.0(6)T
• OSPF Support: 12.0(8)S, 12.1(3)T
• Also in future derivatives of these
trains
Presentation_ID
© 2001, Cisco Systems, Inc.
178
Agenda
• How MPLS TE works
• What Code Is MPLS TE In?
• Platform Issues in Implementation
• Lab Demo - config
Presentation_ID
© 2001, Cisco Systems, Inc.
179
Platform Issues in Implementation
• Basic TE needs software only
RSVP, IS-IS, OSPF, TE
• DS-TE
Needs some form of LLQ
Queueing not tied to advertisement (yet!)
• FRR
Need some quick way to communicate cutover
to LCs
• Label Push/Pop
Could push 2 labels (TE+LDP), 3 if VPN also
Presentation_ID
© 2001, Cisco Systems, Inc.
180
Reading Material
• ENG-59293 – MPLS Forwarding Spec
• ENG-42799 – TE FRR Design Spec
Presentation_ID
© 2001, Cisco Systems, Inc.
181
Agenda
• How MPLS TE works
• What Code Is MPLS TE In?
• Platform Issues in Implementation
• Lab Demo - config
Presentation_ID
© 2001, Cisco Systems, Inc.
182
Core Topology
GSR2
OC3POS
N3
POS0/1
OC3POS
N2
POS0/0
to vpn
AT
MO
C1
2
to vpn
M
AT
GSR1
OC192
N5
POS0/0
POS5/0
12
OC
POS0/0
SRP12
N6
OC48
N4
OC48
N8
POS0/0
OC48
N7
POS3/0
POS1/0
POS2/0
GSR8
POS1/0
POS1/0
GSR5
GSR4
OC12
N10
GSR3
POS2/1
POS2/0
POS1/1
OC12
N11
POS1/0
OC12
N12
GSR7
OC12
N13
POS1/1
POS1/0
GSR6
Presentation_ID
© 2001, Cisco Systems, Inc.
183
TE Topology
VXR12
VXR15
RIP
N21
VXR16
TuAS3402
n11
GSR8
N28
N26
OSPF
N2
7
BGP
9
VXR13
N20
BGP
Tun12
Tun15
N2
N22
N2
AS65001 4
3
N2
N25
GSR1
N3
0
VXR14
VXR10
AS65501
N31
VXR11
VXR9
NOTE: Tun12 and Tun15
flow across the bottom
(long) path and are
protected via the top
path.
Presentation_ID
© 2001, Cisco Systems, Inc.
184