Three planes in networks
Prof. Malathi Veeraraghavan
Elec. & Comp. Engg. Dept/CATT
Polytechnic University
mv@poly.edu
M. Veeraraghavan
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User plane, control plane, and
management plane
• Management plane: consists of all the protocols needed to “configure”
data tables for the operation of the network
– For example, protocols for routing data dissemination (distributed or
centralized)
– Other functions: performance, fault mgmt., accounting, security
• Control plane:
– Connection control protocols
• in CO networks, this includes connection setup at each switch (connections at
the network layer)
• in CL networks, this includes connection setup only at the endpoints
(connections at the transport layer, if the TL protocol is reliable)
– Call control protocols
• User plane: protocols for the actual flow of data
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Routing protocol in all three types of
networks - Phase 1
II
Host A
Routing
protocol
I
Dest.
Next hop
III-*
IV
Routing
protocol
Next hop
III-*
III
Next hop
B
B
Host B
III
Routing
protocol
IV
Dest.
Dest.
V
Routing tables
• Routing protocols exchange
topology/loading/reachability information
• Routes to destinations are precomputed and stored in
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M. Veeraraghavan
routing tables
Signaling protocol for NL connection setup in
a PS CO network - Phase 2
Connection
setup (B)
a
Host A
IN
Port /Label
a/L1
IN
Port /Label
II
d/L1
b
I
c
Connection
setup
b
a
Connection
setup
IV
III
d
c
IN
Port /Label
b
Host B
c
V
d
OUT
Port/Label
a/L2
•
b/L3
a
OUT
Port/Label
c/L2
OUT
Port/Label
c/L1
Connection
setup
Virtual circuit
Connection setup consists of each switch on the path
– Route lookup for next hop node to reach destination
– CAC (Connection Admission Control) for buffer and BW
– Writing the input/output label mapping tables and programming the scheduler
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Signaling protocol for NL connection setup in
a CS CO network - Phase 2
Connection
setup (B)
a
Host A
d/2
b
I
b/1
a
Connection
setup
Connection
setup
b
c
III
b
c
d
c
IV
a
IN
OUT
Port /Timeslot Port/Timeslot
a/1
IN
OUT
Port /Timeslot Port/Timeslot
II
Host B
V
d
Connection
setup
IN
OUT
Port /Timeslot Port/Timeslot
c/2
a/2
Circuit
c/2
• Connection setup consists of each switch on the path
– Route lookup for next hop node to reach destination
– CAC (Connection Admission Control) for BW (note: no buffers)
– Writing the port/timeslot/λ
5 mapping table
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M. Veeraraghavan
User-plane packet forwarding in a PS
CO network - Phase 3
II
L1
b
Host A
IN
Port /Label
a/L1
a
I
c
L1
III
c
d
b
a
OUT
Port/Label
c/L2
L3
a
IV
d
b
Host B
c
V
L2
• Labels are VPI/VCIs in ATM
• Labels are translated from link-to-link
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User-plane actions in a circuit-switched
network - Phase 3
II
1
Host A
2
a
b
I
1
a
1
c
b
a
2
III
d
c
IV
2
b
c
Host B
V
d
IN
OUT
Port /Timeslot Port/Timeslot
a/1
1
c/2
2
• Bits arriving at switch I on time slot 1 on
port a are switched to time slot 2 of port c
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User-plane packet forwarding in a CL PS
network - Phase 3
II
b
Host A
a
I
c
B
B
a
b
a
IV
B
III
c
d
d
b
Host B
c
V
B
• Packet headers carry destination host address (unchanged
as it passes hop by hop)
• Each CL packet switch does a route lookup to determine
the outgoing port/next hop node
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Addressing
• Where are endpoint addresses used:
– In CL PS networks, endpoint addresses are
carried in packet headers
– In CO networks, be it PS or CS, endpoint
addresses are carried in connection setup
messages
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Polytechnic University
Summarized addresses
• What are summarized addresses?
• Why summarize addresses?
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Summarized addresses
• What are summarized addresses?
– An address that represents a group of endpoint
addresses
– e.g., all 212 numbers, 128.238 IP addresses
• Why summarize addresses?
– Reduces routing table sizes – hold one entry for a
summarized address instead of a large number of
individual addresses
– Reduces routing message lengths that convey
reachability information
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Examples of signaling protocols
• SS7 (Signaling System No. 7) network
(with its SS7 protocol stack) carries
signaling messages to set up and release
circuits in a telephone network
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Examples of routing protocols
• In the Internet:
– Link-state routing protocols, such as Open Path
Shortest First (OSPF)
– Distance-vector based routing protocols, such
as Routing Information Protocol (RIP)
• In telephone networks:
– Real-Time Network Routing (RTNR)
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Examples of addressing schemes
• Internet
– 4-byte IP addresses
• Telephone networks
– 8-byte E.164 address (telephone number)
• ATM networks
– 20-byte ATM End System Address (AESA)
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