Campus Networks

How To: Configure Multicast Traffic Flow on Brocade Switches

by brcd-sp.expert on ‎05-07-2012 12:11 PM - edited on ‎04-09-2014 04:59 PM by pmadduru (6,894 Views)

 

 

BRCD-SP 2712

 

Contents

 Overview

 Brocade Layer 3 Switches support the multicast routing protocol Distance Vector Multicast Routing Protocol (DVMRP) and Protocol Interface Multicast (PIM) along with the Internet Group Membership Protocol (IGMP). PIM and DVMRP are broadcast and pruning multicast protocol that deliver IP multicast datagrams. The protocol employs reverse path lookup check and pruning to allow source-specific multicast delivery trees to reach all group members. DVMRP and PIM build a different multicast tree for each source and destination host groups. Multicast protocols allow a group or channel to be accessed over different networks by multiple stations (clients) for the receipt and transmit of multicast data (Figure 1).  Examples of Multicast traffic include distribution of stock quotes, video transmissions such as news services and remote classrooms, and video conferencing that can be accessed over different networks.

 

Figure 1: Transmission of Multicast Packets from the Source to Host Group Members

 

10791_Figure 1- Transmission of Multicast Packets.bmp

 

IPv4 Multicast Address

 

 Host groups are identified as Class “D” IP address, i.e. from 224.0.0.0 to 239.255.255.255. RFC 3171 does not allow IP Multicast Address from 224.0.0.0 to 224.0.0.255 should NOT be forwarded in the internet even if Time To Live (TTL) is configured.

 

Brocade Layer 3 Switches support the multicast routing protocol DVMRP and PIM along with the Internet Group Membership Protocol (IGMP). PIM and DVMRP are broadcast and pruning multicast protocol that deliver IP multicast datagrams. The protocol employs reverse path lookup check and pruning to allow source-specific multicast delivery trees to reach all group members. DVMRP and PIM build a different multicast tree for each source and destination host groups.

 

Terms and Explanations

 

Node – A node is a router or a switch.

Root Node – The seed router that sends multicast packets to downstream multicast delivery tree.

Upstream – Direction from which the router receives the multicast packets.

Downstream – Direction to which the router sends the multicast packets after it receives from upstream node.

Group Presence – When a multicast group has been learnt from one of the directly connected interface of a node.

Intermediate Nodes – Routers that are in patch from the source routers and leaf routers.

Leaf Node – Routers that do not have any downstream routers.

Multicast Tree – Comprised of a root node and one or more of intermediate and leaf nodes for each Source Group.

 

Defining the maximum number of DVMRP cache entries

 

The DVMRP cache system parameter defines the maximum number of repeated DVMRP traffic being sent from the same source address and being received by the same destination address. To define this maximum, enter a command such as the following.

 

Brocade(config)#system-max dvmrp-mcache 500

Syntax: cos <number>

 

The < num> parameter specifies the maximum number of multicast cache entries for DVMRP. Enter a number from 128 – 4096. The default is 512.

 

Defining the maximum number of PIM cache entries

 

The PIM cache system parameter defines the maximum number of repeated PIM traffic being sent from the same source address and being received by the same destination address. To define this maximum, enter a command such as the following.

 

Brocade(config)#system-max pim-mcache 999

 

Allocating Memory for Multicast Protocol

 

The Brocade software allocates memory for each multicast group. It also allocates memory separately for each IGMP interface that becomes part of the multicast group member.

 

 The same group can allocate memory from its multicast group and also from each interface that is part of that the multicast group.

 

Adding an Interface to Multicast Group

 

When you manually add an interface to a multicast group, the Brocade device forwards multicast packets for the group but does not itself accept packets for the group.

 

Brocade(config-if-1/1)#ip igmp static-group 224.2.2.2

 

A virtual routing interface can also be added to a multicast group.

 

Brocade(config-vif-1)#ip igmp static-group 224.2.2.2 ethernet 5/2

 

This command adds port 5/2 in virtual routing interface 1 to multicast group 224.2.2.2.

 

 Configuration Check

 You can check the IGMP group in a Brocade switch by using the command show ip igmp group.

 For further configuration details please visit www.brocade.com

Brocade FastIron Switches (FCX, FSX and ICX)

 

 

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