CS 4594 Broadband

1
CS 4594 Broadband

• PNNI Signaling

2
PNNI

• PNNI Private Network to Network Interface
• Can be used for both public and private networks

3
Two Parts of PNNI

• Topology Distribution Protocol Establish
  structure on an unstructured network
• Signaling Protocol Establish a connection in a
  network

4
PNNI ATM Forum

• From the ATM Forum af-pnni-0055.000 PNNI
  consists of
• A protocol is defined for distributing topology
  information between switches and clusters of
  switches. This information is used to compute
  paths through the network. A hierarchy mechanism
  ensures that this protocol scales well for large
  world-wide ATM networks. A key feature of the
  PNNI hierarchy mechanism is its ability to
  automatically configure itself in networks in
  which the address structure reflects the
  topology. PNNI topology and routing is based on
  the well-known link-state routing technique.
• A second protocol is defined for signaling, that
  is message flows used to establish point-to-point
  and point-to-multipoint connections across the
  ATM network. This protocol is based on the ATM
  Forum UNI signaling, with mechanisms added to
  support source routing, crankback, and alternate
  routing of call setup requests in case of
  connection setup failure.

5
Functions of the PNNI routing protocol

• Discovery of neighbors and link status.
• Election of PGLs. (Peer Group Leader)
• Construction of the routing hierarchy.
• Synchronization of topology databases.

6
Hello establishes local topology

• Each node exchanges Hello packets with its
  immediate neighbors and thereby determines its
  local state information. This state information
  includes the identity and peer group membership
  of the nodes immediate neighbors, and the status
  of its links to the neighbors. Each node then
  bundles its state information in PNNI Topology
  State Elements (PTSEs), which are reliably
  flooded throughout the peer group.

7
Example Network No Hierarchical Structure
C.1
C.2
B.1.1
B.2.1
B.1.2
B.2.3
B.2.2
B.3.2
Source A.1.2.x
B.1.3
A.2.1
B.3.1
B.3.3
B.3.4
A.2.2
A.2.3
B.3.5
A.1.1
A.3.2
A.3.3
A.1.2
Destination B.3.3.y
A.3.4
A.3.1
Level 96
Level 96
8
Structure

• Peer Groups are determined by addressing.
• Address levels are determined by how many bits
  are allocated to the peer group part of the
  address.
• Peer Group Leaders are determined by election.
• Reachability information is determined by
  exchange of information among nodes.
• Uplinks are established using physical links
  between members of different peer groups.

9
The Network Structured
Level 64
A
C
B
A.2
Level 96
Level 80
C.1
C.2
B.1
B.2
B.3
A.1
A.3
B.1.1
B.2.1
Level 72
B.1.2
B.2.3
B.2.2
B.3.2
B.1.3
A.2.1
B.3.1
B.3.3
B.3.4
Level 96
Level 96
A.2.2
A.2.3
B.3.5
A.1.1
A.3.2
Level 96
A.3.3
Level 104
A.1.2
A.3.4
A.3.1
Level 96
Level 96
10
Some Uplinks
Level 64
A
C
B
A.2
Level 96
Level 80
C.1
C.2
B.1
B.2
B.3
A.1
A.3
B.1.1
B.2.1
Level 72
B.1.2
B.2.3
B.2.2
B.3.2
B.1.3
A.2.1
B.3.1
B.3.3
B.3.4
Level 96
Level 96
A.2.2
A.2.3
B.3.5
A.1.1
A.3.2
Level 96
A.3.3
Level 104
A.1.2
A.3.4
A.3.1
Level 96
Level 96
11
The Logical Links are Supported by Uplinks
Level 64
A
C
B
A.2
Level 96
Level 80
C.1
C.2
B.1
B.2
B.3
A.1
A.3
B.1.1
B.2.1
Level 72
B.1.2
B.2.3
B.2.2
B.3.2
Source A.1.2.x
B.1.3
A.2.1
B.3.1
B.3.3
B.3.4
Level 96
Level 96
A.2.2
A.2.3
B.3.5
A.1.1
A.3.2
Level 104
Level 96
A.3.3
A.1.2
Destination B.3.3.y
A.3.4
A.3.1
Level 96
Level 96
12
Problem Establish a Route

• Given Source and Destination and Network as it
  is known at each node.
• Establish a route.

13
The Source and Destination
Level 64
A
C
B
A.2
Level 96
Level 80
C.1
C.2
B.1
B.2
B.3
A.1
A.3
B.1.1
B.2.1
Level 72
B.1.2
B.2.3
B.2.2
B.3.2
Source A.1.2.x
B.1.3
A.2.1
B.3.1
B.3.3
B.3.4
Level 96
Level 96
A.2.2
A.2.3
B.3.5
A.1.1
A.3.2
Level 104
Level 96
A.3.3
A.1.2
Destination B.3.3.y
A.3.4
A.3.1
Level 96
Level 96
14
Possible Route 1A
Level 64
A
C
B
A.2
Level 96
Level 80
C.1
C.2
B.1
B.2
B.3
A.1
A.3
B.1.1
B.2.1
Level 72
B.1.2
B.2.3
B.2.2
B.3.2
Source A.1.2.x
B.1.3
A.2.1
B.3.1
B.3.3
B.3.4
Level 96
Level 96
A.2.2
A.2.3
B.3.5
A.1.1
A.3.2
Level 104
Level 96
A.3.3
A.1.2
Destination B.3.3.y
A.3.4
A.3.1
Level 96
Level 96
15
Possible Route 1B
Level 64
A
C
B
A.2
Level 96
Level 80
C.1
C.2
B.1
B.2
B.3
A.1
A.3
B.1.1
B.2.1
Level 72
B.1.2
B.2.3
B.2.2
B.3.2
Source A.1.2.x
B.1.3
A.2.1
B.3.1
B.3.3
B.3.4
Level 96
Level 96
A.2.2
A.2.3
B.3.5
A.1.1
A.3.2
Level 104
Level 96
A.3.3
A.1.2
Destination B.3.3.y
A.3.4
A.3.1
Level 96
Level 96
16
Possible Route 2A
Level 64
A
C
B
A.2
Level 96
Level 80
C.1
C.2
B.1
B.2
B.3
A.1
A.3
B.1.1
B.2.1
Level 72
B.1.2
B.2.3
B.2.2
B.3.2
Source A.1.2.x
B.1.3
A.2.1
B.3.1
B.3.3
B.3.4
Level 96
Level 96
A.2.2
A.2.3
B.3.5
A.1.1
A.3.2
Level 104
Level 96
A.3.3
A.1.2
Destination B.3.3.y
A.3.4
A.3.1
Level 96
Level 96
17
Yet Another Route (3A)
Level 64
A
C
B
A.2
Level 96
Level 80
C.1
C.2
B.1
B.2
B.3
A.1
A.3
B.1.1
B.2.1
Level 72
B.1.2
B.2.3
B.2.2
B.3.2
Source A.1.2.x
B.1.3
A.2.1
B.3.1
B.3.3
B.3.4
Level 96
Level 96
A.2.2
A.2.3
B.3.5
A.1.1
A.3.2
Level 104
Level 96
A.3.3
A.1.2
Destination B.3.3.y
A.3.4
A.3.1
Level 96
Level 96
18
Basic Concepts

• Designated Transit List (DTL)
• DTLs map out routes.
• DTLs work at different levels.
• A stack keeps track of the levels.
• Call SETUP Message
• is passed to next node.
• is saved at nodes that add new routes.

19
Some Problems

• The link between A.3.3 and B.1.2 is blocked (even
  though PNNI routing says it is OK)
• The link between A.3.3 and B.2.3 cannot support
  the high peak cell rate requested.

20
The Network with Problems
Level 64
A
C
B
A.2
Level 96
Level 80
C.1
C.2
B.1
B.2
B.3
A.1
A.3
B.1.1
B.2.1
Level 72
B.1.2
B.2.3
B.2.2
B.3.2
Source A.1.2.x
B.1.3
A.2.1
B.3.1
B.3.3
B.3.4
Level 96
Level 96
A.2.2
A.2.3
B.3.5
A.1.1
A.3.2
Level 96
A.3.3
Level 104
A.1.2
Destination B.3.3.y
A.3.4
A.3.1
Level 96
Level 96
21
Begin at the Source, Use Route 1
Level 64
A
C
B
A.2
Level 96
Level 80
C.1
C.2
B.1
B.2
B.3
A.1
A.3
B.1.1
B.2.1
Level 72
B.1.2
B.2.3
B.2.2
B.3.2
Source A.1.2.x
B.1.3
A.2.1
B.3.1
B.3.3
B.3.4
Level 96
Level 96
A.2.2
A.2.3
B.3.5
A.1.1
A.3.2
Level 104
Level 96
A.3.3
A.1.2
Destination B.3.3.y
A.3.4
A.3.1
Level 96
Level 96
22
Find Route Through A and A.1
Level 64
A
C
B
A.2
Level 96
Level 80
C.1
C.2
B.1
B.2
B.3
A.1
A.3
B.1.1
B.2.1
Level 72
B.1.2
B.2.3
B.2.2
B.3.2
Source A.1.2.x
B.1.3
A.2.1
B.3.1
B.3.3
B.3.4
Level 96
Level 96
A.2.2
A.2.3
B.3.5
A.1.1
A.3.2
Level 104
Level 96
A.3.3
A.1.2
Destination B.3.3.y
A.3.4
A.3.1
Level 96
Level 96
23
Call SETUP Begins

• SETUP Message saved at A.2.1
• Message forwarded to next node.

24
Push Route from A to B

• DTL A, B, pointer-1

Level 64
A
C
B
Source A.1.2.x
A.2
A.1
A.1.1
A.3
A.1.2
Level 72
25
Push Route Through A

• DTL A.1, A.2, A.3, pointer-1
• DTL A, B, pointer-1

Level 64
A
C
B
Source A.1.2.x
A.2
A.1
A.1.1
A.3
A.1.2
Level 72
26
Push Route Through A.1

• DTL A.1.2, A.1.1, pointer-1
• DTL A.1, A.2, A.3, pointer-1
• DTL A, B, pointer-1

Level 64
A
C
B
Source A.1.2.x
A.2
A.1
A.1.1
A.3
A.1.2
Level 72
27
Move to Next Node in top DTL

• DTL A.1.2, A.1.1, pointer-2
• DTL A.1, A.2, A.3, pointer-1
• DTL A, B, pointer-1

Level 64
A
C
B
Source A.1.2.x
A.2
A.1
A.1.1
A.3
A.1.2
Level 72
28
Pop DTL Stack and Move to A.2

• DTL A.1, A.2, A.3, pointer-2
• DTL A, B, pointer-1

Level 64
A
C
B
A.2
A.1
A.3
Level 72
29
Push a Route through A.2

• DTL A.2.2, A.2.3, pointer-1
• DTL A.1, A.2, A.3, pointer-2
• DTL A, B, pointer-1

Level 64
A
C
B
A.2
A.2.1
A.1
A.3
A.2.2
A.2.3
Level 72
Level 96
30
Call SETUP saved at node

• New route, so save SETUP message at node A.2.2.

31
Move through A.2

• DTL A.2.2, A.2.3, pointer-2
• DTL A.1, A.2, A.3, pointer-2
• DTL A, B, pointer-1

Level 64
A
C
B
A.2
A.2.1
A.1
A.3
A.2.2
A.2.3
Level 72
Level 96
32
Route Through A.2
Level 64
A
C
B
A.2
Level 96
Level 80
C.1
C.2
B.1
B.2
B.3
A.1
A.3
B.1.1
B.2.1
Level 72
B.1.2
B.2.3
B.2.2
B.3.2
Source A.1.2.x
B.1.3
A.2.1
B.3.1
B.3.3
B.3.4
Level 96
Level 96
A.2.2
A.2.3
B.3.5
A.1.1
A.3.2
Level 104
Level 96
A.3.3
A.1.2
Destination B.3.3.y
A.3.4
A.3.1
Level 96
Level 96
33
Pop DTL Stack and Move to A.3

• DTL A.1, A.2, A.3, pointer-3
• DTL A, B, pointer-1

Level 64
A
C
B
A.2
A.1
A.3
Level 72
34
Push a Route through A.3

• DTL A.3.4, A.3.2, A.3.3, pointer-1
• DTL A.1, A.2, A.3, pointer-3
• DTL A, B, pointer-1

Level 64
A
C
B
A.2
A.3.2
A.1
A.3.3
A.3
A.3.4
A.3.1
Level 72
Level 96
35
Save Call SETUP

• New route, so save SETUP message at A.3.4.

36
Move to next node

• DTL A.3.4, A.3.2, A.3.3, pointer-2
• DTL A.1, A.2, A.3, pointer-3
• DTL A, B, pointer-1

Level 64
A
C
B
A.2
A.3.2
A.1
A.3.3
A.3
A.3.4
A.3.1
Level 72
Level 96
37
Go to end of A.3

• DTL A.3.4, A.3.2, A.3.3, pointer-3
• DTL A.1, A.2, A.3, pointer-3
• DTL A, B, pointer-1

Level 64
A
C
B
A.2
A.3.2
A.1
A.3.3
A.3
A.3.4
A.3.1
Level 72
Level 96
38
Pop DTL Stack

• DTL A.1, A.2, A.3, pointer-3
• DTL A, B, pointer-1

Level 64
A
C
B
A.2
A.1
A.3
Level 72
39
Pop DTL Stack, Look for B

• DTL A, B, pointer-2

Level 64
A
C
B
40
Call is Blocked

• At this point the call is blocked A.3.3 finds
  it cannot use the connection to B.1.2

41
Route 1 is Blocked into B
Level 64
A
C
B
A.2
Level 96
Level 80
C.1
C.2
B.1
B.2
B.3
A.1
A.3
B.1.1
B.2.1
Level 72
B.1.2
B.2.3
B.2.2
B.3.2
Source A.1.2.x
B.1.3
A.2.1
B.3.1
B.3.3
B.3.4
Level 96
Level 96
A.2.2
A.2.3
B.3.5
A.1.1
A.3.2
Level 104
Level 96
A.3.3
A.1.2
Destination B.3.3.y
A.3.4
A.3.1
Level 96
Level 96
42
Crankback begins at A.3.3
Level 64
A
C
B
A.2
Level 96
Level 80
C.1
C.2
B.1
B.2
B.3
A.1
A.3
B.1.1
B.2.1
Level 72
B.1.2
B.2.3
B.2.2
B.3.2
Source A.1.2.x
B.1.3
A.2.1
B.3.1
B.3.3
B.3.4
Level 96
Level 96
A.2.2
A.2.3
B.3.5
A.1.1
A.3.2
Level 104
Level 96
A.3.3
A.1.2
Destination B.3.3.y
A.3.4
A.3.1
Level 96
Level 96
43
Crankback

• It cranks back to A.3.4 which attempts alternate
  routing.

44
Crankback to A.3.4
Level 64
A
C
B
A.2
Level 96
Level 80
C.1
C.2
B.1
B.2
B.3
A.1
A.3
B.1.1
B.2.1
Level 72
B.1.2
B.2.3
B.2.2
B.3.2
Source A.1.2.x
B.1.3
A.2.1
B.3.1
B.3.3
B.3.4
Level 96
Level 96
A.2.2
A.2.3
B.3.5
A.1.1
A.3.2
Level 104
Level 96
A.3.3
A.1.2
Destination B.3.3.y
A.3.4
A.3.1
Level 96
Level 96
45
Crankback

• A.3.4 cannot find a route.
• It cranks back to A.1.2 which then attempts
  alternate routing.
• RELEASE message.

46
Crankback to A.1.2
Level 64
A
C
B
A.2
Level 96
Level 80
C.1
C.2
B.1
B.2
B.3
A.1
A.3
B.1.1
B.2.1
Level 72
B.1.2
B.2.3
B.2.2
B.3.2
Source A.1.2.x
B.1.3
A.2.1
B.3.1
B.3.3
B.3.4
Level 96
Level 96
A.2.2
A.2.3
B.3.5
A.1.1
A.3.2
Level 104
Level 96
A.3.3
A.1.2
Destination B.3.3.y
A.3.4
A.3.1
Level 96
Level 96
47
Find an Alternate Route from A.1.2 to B
Level 64
A
C
B
A.2
Level 96
Level 80
C.1
C.2
B.1
B.2
B.3
A.1
A.3
B.1.1
B.2.1
Level 72
B.1.2
B.2.3
B.2.2
B.3.2
Source A.1.2.x
B.1.3
A.2.1
B.3.1
B.3.3
B.3.4
Level 96
Level 96
A.2.2
A.2.3
B.3.5
A.1.1
A.3.2
Level 104
Level 96
A.3.3
A.1.2
Destination B.3.3.y
A.3.4
A.3.1
Level 96
Level 96
48
Push DTLs Through A and A.1

• DTL A.1.2, A.1.1, pointer-2
• DTL A.1, A.2, pointer-1
• DTL A, B, pointer-1

Level 64
A
C
B
Source A.1.2.x
A.2
A.1
A.1.1
A.3
A.1.2
Level 72
49
Pop A.1 and Move to A.2

• DTL A.1, A.2, pointer-1
• DTL A, B, pointer-1

Level 64
A
C
B
Source A.1.2.x
A.2
A.1
A.1.1
A.3
A.1.2
Level 72
50
Push Route through A.2

• DTL A.2.2, A.2.1, pointer-2
• DTL A.1, A.2, pointer-2
• DTL A, B, pointer-1

Level 64
A
C
B
A.2
A.2.1
A.1
A.3
A.2.2
A.2.3
Level 72
Level 96
51
Pop A.2

• DTL A.1, A.2, pointer-2
• DTL A, B, pointer-1

Level 64
A
C
B
A.2
A.2.1
A.1
A.3
A.2.2
A.2.3
Level 72
Level 96
52
Pop A.2

• DTL A, B, pointer-2

Level 64
A
C
B
53
Continue the Path Into B
Level 64
A
C
B
A.2
Level 96
Level 80
C.1
C.2
B.1
B.2
B.3
A.1
A.3
B.1.1
B.2.1
Level 72
B.1.2
B.2.3
B.2.2
B.3.2
B.1.3
A.2.1
B.3.1
B.3.3
B.3.4
Level 96
Level 96
A.2.2
A.2.3
B.3.5
A.1.1
A.3.2
Level 96
A.3.3
Level 104
A.1.2
A.3.4
A.3.1
Level 96
Level 96
54
Push DTLs Through B and B.1

• DTL B.1.1, B.1.3, pointer-2
• DTL B.1, B.2, B.3, pointer-1
• DTL A, B, pointer-2

Level 64
A
C
B
Level 80
B.1.1
B.1
B.2
B.3
B.1.2
B.1.3
Level 96
55
The Path Continues through B.1
Level 64
A
C
B
A.2
Level 96
Level 80
C.1
C.2
B.1
B.2
B.3
A.1
A.3
B.1.1
B.2.1
Level 72
B.1.2
B.2.3
B.2.2
B.3.2
B.1.3
A.2.1
B.3.1
B.3.3
B.3.4
Level 96
Level 96
A.2.2
A.2.3
B.3.5
A.1.1
A.3.2
Level 96
A.3.3
Level 104
A.1.2
A.3.4
A.3.1
Level 96
Level 96
56
Pop B.1, Push Through B.2

• DTL B.2.2, B.2.1, B.2.3, pointer-2
• DTL B.1, B.2, B.3, pointer-2
• DTL A, B, pointer-2

Level 64
A
C
B
Level 80
B.1
B.2
B.3
B.2.1
B.2.3
B.2.2
57
Move to End of B.2

• DTL B.2.2, B.2.1, B.2.3, pointer-2
• DTL B.1, B.2, B.3, pointer-2
• DTL A, B, pointer-2

Level 64
A
C
B
Level 80
B.1
B.2
B.3
B.2.1
B.2.3
B.2.2
58
The Path Continues through B.2
Level 64
A
C
B
A.2
Level 96
Level 80
C.1
C.2
B.1
B.2
B.3
A.1
A.3
B.1.1
B.2.1
Level 72
B.1.2
B.2.3
B.2.2
B.3.2
B.1.3
A.2.1
B.3.1
B.3.3
B.3.4
Level 96
Level 96
A.2.2
A.2.3
B.3.5
A.1.1
A.3.2
Level 96
A.3.3
Level 104
A.1.2
A.3.4
A.3.1
Level 96
Level 96
59
Pop B.2, Push Through B.3

• DTL B.3.4, B.3.1, B.3.3, pointer-2
• DTL B.1, B.2, B.3, pointer-3
• DTL A, B, pointer-2

Level 64
A
C
B
B.3.2
B.3.1
Level 80
B.1
B.2
B.3
B.3.3
B.3.4
B.3.5
Level 104
60
Move to End of B.3

• DTL B.3.4, B.3.1, B.3.3, pointer-2
• DTL B.1, B.2, B.3, pointer-3
• DTL A, B, pointer-2

Level 64
A
C
B
B.3.2
B.3.1
Level 80
B.1
B.2
B.3
B.3.3
B.3.4
B.3.5
Level 104
61
Pop the Stack

• Pop B.3
• Pop B
• At the destination
• Now stack is empty and we are done.

62
Send back CONNECT message
63
The Path Is Established
Level 64
A
C
B
A.2
Level 96
Level 80
C.1
C.2
B.1
B.2
B.3
A.1
A.3
B.1.1
B.2.1
Level 72
B.1.2
B.2.3
B.2.2
B.3.2
Source A.1.2.x
B.1.3
A.2.1
B.3.1
B.3.3
B.3.4
Level 96
Level 96
A.2.2
A.2.3
B.3.5
A.1.1
A.3.2
Level 96
A.3.3
Level 104
A.1.2
Destination B.3.3.y
A.3.4
A.3.1
Level 96
Level 96