IP global parameters for routing switches

The following table lists the IP global parameters and the page where you can find more information about each parameter.

IP global parameters for routing switches




See page

Router ID

The value that routers use to identify themselves to other routers when exchanging route information. OSPF uses the router ID to identify routers.RIP does not use the router ID.

The lowest-numbered IP address configured on the lowest-numbered routing interface.

Changing the router ID

Address Resolution Protocol (ARP)

A standard IP mechanism that routers use to learn the MAC address of a device on the network. The router sends the IP address of a device in the ARP request and receives the device's MAC address in an ARP reply.


Configuring ARP parameters

ARP age

The amount of time the device keeps a MAC address learned through ARP in the device's ARP cache. The device resets the timer to zero each time the ARP entry is refreshed and removes the entry if the timer reaches the ARP age. See Increasing ARP age timeout (CLI).

Five minutes.


Proxy ARP

An IP mechanism a router can use to answer an ARP request on behalf of a host, by replying with the router's own MAC address instead of the host's.


About enabling proxy ARP

Time to Live (TTL)

The maximum number of routers (hops) through which a packet can pass before being discarded. Each router decreases a packet's TTL by 1 before forwarding the packet. If decreasing the TTL causes the TTL to be 0, the router drops the packet instead of forwarding it.

64 hops

See the Management and Configuration Guide for your switch.

Directed broadcast forwarding

A directed broadcast is a packet containing all ones (or in some cases, all zeros) in the host portion of the destination IP address. When a router forwards such a broadcast, it sends a copy of the packet out each of its enabled IP interfaces. You also can enable or disable this parameter on an individual interface basis. See IP interface parameters for routing switches .


Enabling forwarding of directed broadcasts

ICMP Router Discovery Protocol (IRDP)

An IP protocol that a router can use to advertise the IP addresses of its router interfaces to directly attached hosts. You can enable or disable the protocol at the Global CLI Config level. You also can enable or disable IRDP and configure the following protocol parameters on an individual VLAN interface basis at the VLAN Interface CLI Config level.
  • Forwarding method (broadcast or multicast)

  • Hold time

  • Maximum advertisement interval

  • Minimum advertisement interval

  • Router preference level


A-21 A-159

Static route

An IP route you place in the IP route table.

No entries


Default network route

The router uses the default network route if the IP route table does not contain a route to the destination. Enter an explicit default route ( or as a static route in the IP route table.

None configured