Dell PowerConnect 6024 User's Guide (.htm) - Page 20
Address Resolution Protocol (ARP), ICMP Messages, IGMPv2, Longest Prefix Match Support, DVMRP, VRRP
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www.dell.com | support.dell.com 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." 30 Introduction
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