By:
Jawad Raza
Manager Network & Operations
jraza@hec.gov.pk
Friday 30th August,2013
NUML
FAST
AIOU
PUUST
Arid
IIU
NUST H-12
BU NDU
IST
FJWU
AUP
PU
IMS
UET
GU
NUST,RWP
QAU
UET
UVAS
HEC(Pesh)
PMA
GCUL
PU-NEW
Legend
KCW
Uop-OLD
NCOEIMB
VU
BUITMS(QTA)
AUF(FSD)
UOB
CSC
SBKWU
GCU
BZU(MLT)
UOA SU
IU(BWP)
FAST
CPSP
HEC(khi)
HU
IBA
NED
SSUET
NCA
LCWU
FAST
UHS
HEC(lhr)
PNA
PIES
HEC(ISB)PASC
KU
UOM
CoAE
GIK
HU
10G Link
1G Link
KU
AKU
DUHS
UET,Khuzdar
LU
USINDH(HYD)
HEJ
QeA
MUET
LUMHS
IBA
SALU
NCP
CIIT
AU
SAU
UOG
LSE
LUMS
UOE
Topology Design
Campus-A
User-A
Core layer
Isb-PoP
•
Level-1:
•
Three (3) cRA-PoP
routers, located at the
major cities of Pakistan
•
Lhr-PoP
•
Level-2:
•
Internet
Service
Provider
•
Five (5) sRA-PoP routers,
located at the small
cities
Level-3:
•
Seven (7) LA-PoP router,
to cover the metro cities
User-B
Campus-B
Khi-PoP
User-C
NRENs Link
TEIN3 Network
Stanford University,
Campus-A
User-A
Core layer
1.
Isb-PoP
Level-1:
1.
Lhr-PoP
1.
Level-2:
1.
Internet
Service
Provider
2.
Campus-B
Khi-PoP
NRENs Link
TEIN3 Network
Five (5) sRA-PoP routers,
located at the small
cities
Level-3:
1.
User-B
Three (3) cRA-PoP
routers, located at the
major cities of Pakistan
Seven (7) LA-PoP router,
to cover the metro cities
Campus-A
User-A
Traffic Categories
Isb-PoP
•
A – Internet traffic:
•
IP Transit Connectivity
•
•
Internet
Service
Provider
•
User-B
B – Intranet traffic:
•
Connectivity among the
PERN2 Campuses
•
Intranet Bandwidth
should be Separate from
Internet Bandwidth
C – International NREN
(R&D) traffic
•
Campus-B
Khi-PoP
NRENs Connectivity
TEIN3 Network
For the R&D traffic
Bandwidth must be
separate from Intranet
and Internet
Stanford (USA)

IPv4 Addressing

Routing & Forwarding

Routing Protocols
◦ IGPs
◦ EGP


What does the router do?
Find path & forward packet…… if primary
path is not available find alternate path….

Routing:
◦ Selection of Path in the networks along with which to send
network traffic

Forwarding:
◦ Moving packets between interfaces according to the
“directions”

Path derived from information received from a routing
protocol

Several alternative paths may exist best next hop stored
in forwarding table

Decisions are updated periodically or as topology
changes (event driven)

Decisions are based on:
◦ Topology, policies and metrics (hop count, filtering, delay,
bandwidth, etc.

Based on destination IP packets
40/8
R3
Packet Destination:
10.1.1.1
R1
R2
10/16 R4
20/8 R6
30/8  R5
40/8  R30
R4
10/16

32 bits long address,
◦ Range from 1.0.0.0 to 223.255.255.255


Serves with two principal function i.e Network portion
and Host Portion
Address & Mask written as
◦ 192.168.1.1 255.255.255.0 or 192.168.1.1/24

Some of the IP addresses are reserved
◦ Private IP Addresses
◦ Multicast IP Addresses

Interior Gateway Protocols
◦ within a single autonomous system
 single network administration
 unique routing policy
 make best use of network resources

Exterior Gateway Protocols
◦ among different autonomous systems
 independent administrative entities
 communication between independent network
infrastructures
AS 100




Collection of networks with same routing policy
Single routing protocol
Usually under single ownership, trust and administrative control
Identified by a unique number

IGP
◦ RIP
◦ IS-IS
◦ OSPF

EGP
◦ BGP
User-A
Single network
administration
Campus-A
Isb-PoP
IGP
unique routing
policy
Lhr-PoP
Internet
Service
Provider
User-B
Campus-B
Khi-PoP
TEIN3
Network
User-A
Single network
administration
Campus-A
Isb-PoP
IGP
Lhr-PoP
unique routing
policy
EGP
Internet
Service
Provider
User-B
Campus-B
Khi-PoP
TEIN3
Network
User-A
Campus-A
IGPs
1. RIP
2. OSPF
3. IS-IS
Isb-PoP
Lhr-PoP
User-B
Campus-B
Internet
Service
Provider
Khi-PoP
TEIN3
Network

Routing Information Protocol
◦ Two Versions of RIP
 RIPv1
 RIP v2


Distance Vector Routing Protocol
RIPng (Next Generation) design for IPv6
routing

Routers are advertised as vector of distance and direction.

Direction is represented by next hop address and exit
interface.

Whereas Distance uses metrics such as hop count


Updates are performed periodically in a distance vector
protocol where all router's routing table is sent to all its
neighbors
The cost of reaching a destination is calculated using
various route metrics, RIP uses hop count to calculate
metric.



Hop count Limit to 15
RIP eats lots of bandwidth (all broadcast traffic) on large
networks
RIP takes 30 – 60 seconds to converge
User-A
Campus-A
IGPs
1. RIP
2. OSPF
3. IS-IS
Isb-PoP
Lhr-PoP
User-B
Campus-B
Internet
Service
Provider
Khi-PoP
TEIN3
Network

Most Widely used IGP routing protocol

Link State Protocol

Allow routers to dynamically learn routes
from other routers and to advertise routes
to other routers.

OSPF operation can be divided into three
categories
Neighbor and Adjacency initialization
LSA Flooding
SPF Calculation


In a link-state protocol, the network can be viewed as a jigsaw
puzzle
Each jigsaw piece holds one router
LSP for router-B
LSP for router-A
to A
to B
to E
to C
to D
to E
to A
to A
to B
LSP for router E
to D
to B
to C
LSP for router-D
LSP for router-C


Each router creates a packet which represents its own jigsaw piece
This packet is called a Link State Advertisement (LSA)

These packets are flooded everywhere

Therefore each router receives all pieces of the jigsaw puzzle

Each routers compute SPF algorithm to put the pieces
together
Input: all jigsaw puzzle pieces
Output: Area or network topology tree
Shortest Path Tree

All routers exchange all LSAs
via a reliable flooding mechanism Link

Area is a group of
contiguous hosts and
networks
 Reduces routing traffic
Area 2
Area 1
R2
R1
R4
R3


Area 0
Per area topology
database
Backbone Area
R5
Backbone area MUST be
contiguous
◦ All other areas must be
connected to the backbone
R8
R7
R9
Area 3
R6
R11
R10
R12
Area 4

Support Large Network

Fast Update and Convergence

Support VLSM


Dividing the whole routing domain into
different areas
Support Authentication

OSPF for IPv6

Based on OSPFv2, with enhancements

Distributes IPv6 prefixes

Runs directly over IPv6

Ships-in-the-night with OSPFv2
User-A
Campus-A
IGPs
1. RIP
2. OSPF
3. IS-IS
Isb-PoP
Lhr-PoP
User-B
Campus-B
Internet
Service
Provider
Khi-PoP
TEIN3
Network

IS an IGP (Interior Gateway Protocol) scalable only
for dynamic routing within a domain

Link State Protocol

IS a dynamic routing protocol based on SPF
routing algorithm

IS is “OSI speak” for router

Easily extendable for other routing protocol
Mainly IPv6

IS-IS has 2 levels of hierarchy
◦ Level-1 (L1)
 Neighbors only in the same AREA, and information about its
own area
L1 Adjacencies

Embraced by the large tier1 ISPs.

Proven to be a very stable and scalable, with
very fast convergence.

Encodes the packet(s) in TLV format.


Flexible protocol in terms of tuning and
easily extensible to new features (MPLS-TE
etc).
It runs directly over Layer 2. (next to IP).
User-A
Campus-A
IGPs
1. RIP
2. OSPF
3. IS-IS
Isb-PoP
Lhr-PoP
User-B
Campus-B
Internet
Service
Provider
Khi-PoP
TEIN3
Network

Similarities:


OSPF and IS-IS are more similar than they are different.
 Both are Link State Routing Protocol
 Both ISIS & OSPF Support Hierarchical Routing
 Both Support VLSM, CDIR, Authentication, Multiple Paths
ISIS & OSPF Similar Terminologies
◦ OSPF









Host
Router
Link
Packet
Link-State Advertisement (LSA)
Area
Non-backbone area
Backbone area
Area Border Router (ABR)
ISIS
End System (ES)
Intermediate System (IS)
Circuit
Protocol Data Unit (PDU
Link-State PDU (LSP)
Sub domain (area)
Level-1 area
Level-2 Sub domain (backbone)
L1L2 router

Difference:
ISIS
OSPF
Generally supports a up to 1024 nodes in the
same Area
Generally deployed with a much smaller
number of nodes (less than 200).
SPF table not refresh periodically.
OSPF does so after 30min.
Provide more extensibility , for example ISIS
was given new TLVs to Support IPv6.
TLVs can also be utilize to carry MPLS TE
attributes (ISIS-TE)
OSPF was completely re-written to Support
IPv6 (i.e OSPFv3)
ISIS group update into one packet and send
them as one LSP, so to increase network
efficiency
OSPF produce many LSAs

“Which
◦
◦
◦
◦
◦
IGP should an ISP choose?
Both OSPF and ISIS use Dijkstra SPF algorithm
Exhibit same convergence properties
ISIS can runs on data link layer, OSPF runs on IP layer
Biggest ISPs tend to use ISIS
Main ISIS implementations more tuneable than equivalent OSPF
implementations “
CISCO

GEANT2 http://www.geant2.net/server/show/nav.1525 :
“The IGP currently used in GÉANT is the ISO IGP IS-IS (Intermediate System
to
Intermediate System), which provides support for both IPv4 and IPv6”.

CANARIE http://www.canarie.ca/canet4/services/c4_routing_policy.pdf
“The Intermediate System-to-Intermediate System (IS-IS) routing protocol
IGP for CA*net 4, where a single IS-IS Level 2 area is defined. IS-IS
is the
was chosen
over OSPF mainly for network migration considerations as well as for early release of
advanced backbone network feature support by major routing vendors”.

Ufone Pakistan (Largest Telecomm Operator in Pakistan)

China Telecomm

CMPaK (Telecomm Operator in Pakistan)
(An extra-large State-owned telecom operator in China)
IS-IS
ISB-HEC
PSH-HEC
10
10
10
10
Legend
10
10
10G Link
(Optic Fiber)
10G Link
(Long Haul Fiber)
10
10
10
LHR-HEC
FSD-AUF
QTA-BUITMS
10
10
MLT-BZU
10
10
10
10
10
10
10
HYD-USINDH
10
KHI-HEC
IS-IS enable interface
International University Service,
Webserver, Mailserver, etc.
Internet Service
VOIP Service
One interlink ip
NAT and one default route
pointing to NE20E
NE20E
(CPE)
ISIS Core layer
NE40E/80E (PE)
VOD,IPTV,
Streaming, etc.
•
OSPF process Between PoP
Router & Access router
•
Under different
Management
•
Easier to Manage for a
campus environment
GE Optic link
FE Electric link
Internet Service
International University
Service,Webserver,
Mailserver, etc.
VOIP Service
NE20E
(CPE)
One interlink ip
MPLS Backbone
NAT and one default
route pointing to NE20E
VOD,IPTV,
Streaming, etc.
NMS Servers
&Clients.
NE40E/80E (PE)
Subinterface10: enable ISIS/MPLS for L2VPN
Subinterface20: Internet
Subinterface30: NREN
Subinterface40: Intranet
L2VPN Service
CPE:
.
Page 48
Internet
Service
Provider
TEIN3
Network


A Routing protocol used to exchange routing
information between different Networks
The Autonomous System is BGP’s
fundamental operating unit
◦ It is used to uniquely identify networks with a
common routing policy
AS 100




Collection of networks with same routing policy
Single routing protocol
Usually under single ownership, trust and administrative control
Identified by a unique number

Two ranges

Usage:
◦ 0-65535
◦ 65536-4294967295
◦
◦
◦
◦
◦
◦
◦
0 and 65535
1-64495
64496-64511
64512-65534
23456
65536-65551
65552-4294967295
(original 16-bit range)
(32-bit range - RFC4893)
(reserved)
(public Internet)
(documentation - RFC5398)
(private use only)
(represent 32-bit range in 16-bit world)
(documentation - RFC5398)
(public Internet)

ASNs are distributed by the Regional Internet Registries

The RIRs also have received 1024 32-bit ASNs each
◦ They are also available from upstream ISPs who are members of one of the RIRs
◦ Out of 190 allocations, around 50 are visible on the Internet
◦ See www.iana.org/assignments/as-numbers


Multi-homing with BGP is a way to manage redundant links to
multiple ISPs.
Maintaining links to multiple Internet provider (Usually 2 or 3) and
using BGP to send routs and receive full routing tables from these
providers
ISP-1
ISP-2
AS 100
Multi-homed Customer
ISP-1
ISP-2
PE
ISB-HEC-P-PE-EGRESS-NE80E
IBGP
PE
PE
KHI-HEC-P-PE-EGRESS-NE80E
PE
ISP-1
ISP-2
ASN-1
ASN-2
Router Receives Full routing
table from both ISP’s, and
store the best available routes
reveries from both these ISPs,
ASN-2
ASN-1
Primary Prefixs
Primary Prefixs
P5/24
P1/24
P6/24
P2/24
P7/24
P3/24
P8/24
P4/24
Prepend Prefixs
Prepend Prefixs
P1/24
P5/24
P2/24
P6/24
P3/24
P4/24
PERN2 Prefixes
P1/24
P7/24
P8/24
P2/24
P3/24
P4/24
P5/24
P6/24
P7/24
P8/24
BGP Policy routing has been
applied, AS-PATH Prepend for
the
load
balancing
on
Incoming traffic
ASN-2
ASN-1
Primary Prefixs
Primary Prefixs
P5/24
P1/24
P6/24
P2/24
P7/24
P3/24
P8/24
P4/24
Prepend Prefixs
Prepend Prefixs
P1/24
P5/24
P2/24
P6/24
P3/24
P4/24
PERN2 Prefixes
P1/24
P7/24
P8/24
P2/24
P3/24
P4/24
P5/24
P6/24
P7/24
P8/24
In Case of One link failure,
the prefix prepend traffic will
be shifted to backup link.




eBGP is used to learn the Internet Routes and
advertised PERN2 IP prefixes on Internet
iBGP then originate connected networks and also
pass on prefixes learned from outside the ASN
ISIS has been used as an IGP Protocol on the core
network of PERN2
OSPF has been used as an IGP protocol between
the core and access network.

Service Communicator
◦ Generates Tickets
◦ http://sc.hec.gov.pk
◦ 24/7 Help Line also Available i.e
 111-11PERN
 051-9040PERN
◦ Complain also can log by email
pern2noc@hec.gov.pk