Wednesday, January 13, 2016

Multicast task #5. Multicast tuning and redundancy.

Topology:




Use configuration from Multicast task #4 as initial configuration for this task.

Requirements: 

Change the multicast configuration to achieve the below requirements.
You are allowed to remove the existing configuration.
You are allowed use prefix 13.0.254.0/24 to complete this task.
Multicast receivers are using IGMPv2.

1. Minimize the amount entries in multicast routing table.
2. Provide redundancy and fastest possible convergence for RP failure.
3. RP information should be distributed dynamically. 

Solution:

Highlight the text below to reveal the solution.

This task requires understanding of Bidir PIM and Bidir Phantom-RP configuration. 

Requirement #1 - two ways to minimize the amount of required multicast routes are to either use PIM-SSM ( no (*.G) routes) or to use PIM-Bidir (no (S,G) routes). Since receivers are only capable of IGMPv2, then PIM-Bidir should be used for this task. 

Requirement #2 - to provider redundancy and fastest convergence for Bidir RP, use Phantom-RP. 
Select two or more routers to server as RP. Configure new loopback interface from the provided range 13.0.254/24 with different subnet length on each router. Use host address off that loopback as Phantom-RP. * Note that convergence is limited by the IGP convergence speed. Using P2P adjacency or BFD will improve IGP convergence times. Note that OSPF network type for the loopback interface need to be changed to point-to-point, in order to advertise correct network mask. 

Requirement #3 - Phantom-RP can be dynamically distributed only using Auto-RP. BSR does not support advertising IP address, only interface. Note that IOS-XR Auto-RP does not allow to advertise IP address, so only IOS routers can be used as RP in this scenario. 

This solution uses R2 and R5 as RP and Mapping agents, but any IOS routers could be used for solution. 

R1, R6 and R7:


!
ip pim bidir-enable
ip pim autorp listener
!

R2: 


!
interface Loopback1
 ip address 13.0.254.2 255.255.255.0
 ip pim sparse-mode
 ip ospf network point-to-point
!
ip pim bidir-enable
ip pim autorp listener
ip pim send-rp-announce 13.0.254.100 scope 255 bidir
ip pim send-rp-discovery Loopback0 scope 255
!


R5: 


!
interface Loopback1
 ip address 13.0.254.5 255.255.255.128
 ip pim sparse-mode
 ip ospf network point-to-point
!
ip pim bidir-enable
ip pim send-rp-announce 13.0.254.100 scope 255 bidir
ip pim send-rp-discovery Loopback0 scope 255

Verification:

R1#sh ip pim rp mapping
PIM Group-to-RP Mappings

Group(s) 224.0.0.0/4
  RP 13.0.254.100 (?), v2v1, bidir
    Info source: 13.0.5.5 (?), elected via Auto-RP
         Uptime: 00:40:33, expires: 00:02:49

RP/0/0/CPU0:R3#show pim rp mapping
Wed Dec 30 22:54:02.605 UTC
PIM Group-to-RP Mappings
Group(s) 224.0.0.0/4
  RP 13.0.254.100 (?), v2, bidir
    Info source: 13.0.2.2 (?), elected via autorp
      Uptime: 01:31:22, expires: 00:02:55

R1#sh ip pim neighbor
PIM Neighbor Table
Mode: B - Bidir Capable, DR - Designated Router, N - Default DR Priority,
      P - Proxy Capable, S - State Refresh Capable, G - GenID Capable
Neighbor          Interface                Uptime/Expires    Ver   DR
Address                                                            Prio/Mode
13.0.12.2         Ethernet0/0              02:23:34/00:01:23 v2    1 / B S P G
13.0.15.5         Ethernet0/1              00:18:14/00:01:41 v2    1 / B S P G



R5#sh ip mroute 239.66.66.66
IP Multicast Routing Table
Flags: D - Dense, S - Sparse, B - Bidir Group, s - SSM Group, C - Connected,
       L - Local, P - Pruned, R - RP-bit set, F - Register flag,
       T - SPT-bit set, J - Join SPT, M - MSDP created entry, E - Extranet,
       X - Proxy Join Timer Running, A - Candidate for MSDP Advertisement,
       U - URD, I - Received Source Specific Host Report,
       Z - Multicast Tunnel, z - MDT-data group sender,
       Y - Joined MDT-data group, y - Sending to MDT-data group,
       V - RD & Vector, v - Vector
Outgoing interface flags: H - Hardware switched, A - Assert winner
 Timers: Uptime/Expires
 Interface state: Interface, Next-Hop or VCD, State/Mode

(*, 239.66.66.66), 00:17:33/00:02:46, RP 13.0.254.100, flags: B
  Bidir-Upstream: Loopback1, RPF nbr 13.0.254.100
  Outgoing interface list:
    Ethernet0/2, Forward/Sparse, 00:17:33/00:02:46
    Loopback1, Bidir-Upstream/Sparse, 00:17:33/stopped

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