Enterasys Networks Security Router X-PeditionTM - Manual (Page 112)

IP Routing Protocols
5-10 Configuring IP
VRRP & Secondary IP
Multiple virtual IP addresses per Virtual Router (VR) are available to support multiple logical IP
subnets on a single LAN segment. Secondary IP interacts with the XSR’s implementation of the
Virtual Router Redundancy Protocol (VRRP) as follows:
• The primary physical IP address on an interface will be selected as a VRRP primary IP
address, which is used for VRRP advertisement.
• If one of the virtual IP addresses of a VR is the real physical address of the interface, all other
virtual IP addresses of that VR must also be the real physical addresses of that interface.
• Conversely, if any virtual IP address is not the real physical address of that interface, all
virtual IP address of that VR cannot be the real physical address of that interface.
• The XSR supports 11 IP addresses per VR (1 primary + 10 secondary)
• With four VR's allowed per XSR, you can configure up to 44 virtual IP addresses per XSR.
PPPoE & Secondary IP
Secondary IP is not supported on PPPoE interfaces.
Maximum Transmission Unit (MTU)
MTU is the largest frame size allowed on an interface. It is dictated by the link level limit on a
particular port. Examples of link layer types are Ethernet and 802.3 encapsulation. MTU limits the
bytes of data that can be sent in an IP packet using the
ip mtu command. Datagrams exceeding
the link layer's MTU must be fragmented. The default MTU size is 1500 bytes.
Refer to the XSR CLI Reference Guide for more information.
Ping
Ping is an important debugging tool for testing network layer connectivity between a source and
destination address. The source represents an IP address on the XSR where the command is
executed from. The destination can be any IP address on the network, including an address on the
same device where a ping occurs.
Ping also allows the packet size to be set.
Refer to the XSR CLI Reference Guide for more information.
Traceroute
Traceroute is a vital debugging tool which reports the route IP datagrams follow to a certain
destination. Its output is a complete list of routers that a specific datagram crosses to reach its
destination, as well as the round time trip between the XSR where the Traceroute program runs
and each of these routers. The
traceroute command can be issued by the XSR.
Refer to the XSR CLI Reference Guide for more information.
IP Routing Protocols
Routing is one of the most important functions of IP. Routing information, which is stored in a
routing table, is used by the XSR to determine the route for each of the packets that pass through
it. The following routing features are supported on the XSR:
• RIP, OSPF, and BGP