Ip Route Exchange Protocols; Ip Multicast Protocols - Foundry Networks Switch and Router Installation And Configuration Manual

NOTE: You cannot add static entries to the IP forwarding cache, although chassis Layer 3 Switches do have
options to optimize the cache and increase the number of entries the cache can contain. See "Optimizing the IP
Forwarding Cache" on page 15-63 and "Displaying and Modifying System Parameter Default Settings" on
page 10-70.
To increase the size of the IP forwarding cache, see "Displaying and Modifying System Parameter Default
Settings" on page 10-70. The ip-cache parameter controls the size of the IP forwarding cache.
Layer 4 Session Table
The Layer 4 session provides a fast path for forwarding packets. A session is an entry that contains complete
Layer 3 and Layer 4 information for a flow of traffic. Layer 3 information includes the source and destination IP
addresses. Layer 4 information includes the source and destination TCP and UDP ports. For comparison, the IP
forwarding cache contains the Layer 3 destination address but does not contain the other source and destination
address information of a Layer 4 session table entry.
The Layer 2 Switch or Layer 3 Switch selects the session table instead of the IP forwarding table for fast-path
forwarding for the following features:
• Policy-Based Routing (PBR)
• Layer 4 Quality-of-Service (QoS) policies
• IP access policies
To increase the size of the session table, see "Displaying and Modifying System Parameter Default Settings" on
page 10-70. The ip-qos-session parameter controls the size of the session table.

IP Route Exchange Protocols

Foundry Layer 3 Switches support the following IP route exchange protocols:
• Routing Information Protocol (RIP)
• Open Shortest Path First (OSPF)
• Border Gateway Protocol version 4 (BGP4)
All these protocols provide routes to the IP route table. You can use one or more of these protocols, in any
combination. The protocols are disabled by default. For configuration information, see the following:
• "Configuring RIP" on page 16-1
• "Configuring OSPF" on page 17-1
• "Configuring BGP4" on page 19-1

IP Multicast Protocols

Foundry Layer 3 Switches also support the following Internet Group Membership Protocol (IGMP) based IP
multicast protocols:
• Protocol Independent Multicast – Dense mode (PIM-DM)
• Protocol Independent Multicast – Sparse mode (PIM-SM)
• Distance Vector Multicast Routing Protocol (DVMRP)
For configuration information, see "Configuring IP Multicast Protocols" on page 18-1.
NOTE: Foundry Layer 2 Switches support IGMP and can forward IP multicast packets. See "Configuring IP
Multicast Traffic Reduction (Layer 2 Switches only)" on page 10-56.
December 2000
Configuring IP
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