6.3 Multicast Protocol Statements
6.3.1 Protocol Overview
6.3.2 Intra-Domain Routing Protocols
Interior protocols are used to exchange reachability information within an autonomous system
(AS). They are referred to as a class by the acronym igp. There are two interior protocols
currently supported by this version of GateD:
- DVMRP
- Distance Vector Multicast Routing Protocol (DVMRP) is the original IP Multicast
routing protocol. It was designed to run over both multicast capable lans (like Ethernet)
as well as through non-multicast capable routers. In this case, the IP Multicast packets
are "tunneled" through the routers as unicast packets. This replicates the packets and
has an effect on performance, but has provided an intermediate solution for IP Multicast
routing on the Internet while router vendors decide to support native IP Multicast
routing.
- PIM
- PIM was designed to take advantage of two existing multicast routing protocols,
DVMRP and CBT. It exibits the behavior of a protcol in a region of dense group
membership flooding multicast packets using Reverse Path Multicasting, while also
taking advantage of the work done for sparse group membership in Core Based Trees.
Hence, the protocol has two modes: dense mode (PIM-DM), and sparse mode
(PIM-SM). Currently, only dense mode is implemented in Gated
- PIM-DM
- Intermediate System to Intermediate System (ISIS) is a link state interior gateway
protocol (IGP) originally developed for routing ISO/CLNP (International Organization
for Standardization/Connectionless Network Protocol) packets. The version distributed
with GateD can route IP packets as well.
- PIM-SM
6.3.3 Inter-Domain Routing Protocol
- M-BGP
6.3.4 Other Routing Protocols
6.3.5 Other Support
- IGMP
- Internet Group Management Protocol (IGMP) was primarily designed for hosts on
multi-access networks to inform locally attached routers of their group membership
information. This is performed by hosts multicasting IGMP Host Membership Reports.
Multicast routers listen for these messages and can then exchange group membership
information with other multicast routers. This allows distribution trees to be formed to
deliver multicast datagrams.
- MBR
Last updated April 26, 1997 (11:59AM)
gated@gated.merit.edu