D-Link DES-3226S [217/242] Routing protocols

D-Link DES-3326S Layer 3 Switch

two multicast routers on a network have the same distance back to a multicast source, the router with the lowest IP address is

elected.

DVMRP also supports tunnel interfaces, where two multicast routers are connected through a router that cannot process

multicast packets. This allows multicast packets to cross networks with routers that are not multicast-aware.

SM) which is used when the multicast destinations are spaced further apart. PIM-DM is most commonly implemented in an

A router can ‘poison reverse’ a route by adding an infinite (16) hop count to a route’s advertisement. This is usually used in

conjunction with triggered updates, which force a router to send an immediate broadcast when an update of an unreachable

RIP Version 1 Message Format

There are two types of RIP messages: routing information messages and information requests. The same format is used by

both types.

Routing Protocols

The Routing Information Protocol is a distance-vector routing protocol. There are two types of network devices running RIP

– active and passive. Active devices advertise their routes to others through RIP messages, while passive devices listen to

RIP measures distance by an integer count of the number of hops from one network to another. A router is one hop from a

directly connected network, two hops from a network that can be reached through a router, etc. The more routers between a

source and a destination, the greater the RIP distance (or hop count).

When learned routes are entered into the routing table, a timer is started. This timer is restarted every time this route is

mechanism (a password) to prevent a router from learning erroneous routes from unauthorized routers.

network is unreachable) is defined as 16 hops. In other words, if a network is more than 16 routers from the source, the local