Dell PowerConnect 6024 User Manual page 20

Address Resolution Protocol (ARP)
In IP routing, routers and Layer 3 switches use various routing protocols to discover network
topology and define routing tables. ARP automatically determines Device Next-Hop MAC
addresses of systems, including directly attached end systems. Users can override and supplement
this by defining additional ARP table entries.
For information about configuring ARP, see "Defining ARP Settings."
ICMP Messages
Internet Control Message Protocol (ICMP) messages are used for out-of-band messages related to
network operation or malfunction.
IGMPv2
IGMP enables the router to send IGMP queries in the form of L2 broadcasts over each interface.
When a multicast packet is sent, and it has a multicast destination MAC address, all hosts on that
router interface receive a copy. Hosts listen to all IGMP reports. If interested multicast groups have
already been requested by any station on the same interface, the remaining stations do not send
duplicate requests.
For information about configuring IGMP, see "Defining IGMP Interface Parameters."
Longest Prefix Match Support
Longest prefix matches are used primarily to determine the best next-hop route for a packet based
solely on the destination address contained in the packet header. Because IP addresses are generally
assigned in a manner that reflects the topology of the network, the result of a longest prefix match
usually reflects the shortest route to the destination.
DVMRP
Distance Vector Multicast Routing Protocol (DVMRP) advertises the shortest-path routes to
multicasting source networks with hosts that can transmit multicast IP traffic.
For information about configuring DVMRP, see "Configuring DVMRP Interfaces."
VRRP
Virtual Router Redundancy Protocol (VRRP) eliminates single points of failure in the routing
environment. VRRP uses an election protocol that dynamically assigns responsibility for the virtual
router to one of the VRRP routers in the LAN.
The election process provides dynamic failover in the forwarding responsibility, if the master is
unavailable. Any virtual router IP address can be used as a default first-hop router by end-hosts.
For information about configuring VRRP, see "Configuring VRRP."
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Introduction