Foundry Networks Switch and Router Installation And Configuration Manual page 453

Table 15.1: IP Global Parameters – Layer 3 Switches (Continued)
Parameter Description
Time to Live The maximum number of routers (hops) through
(TTL) 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.
Directed A directed broadcast is a packet containing all ones
broadcast (or in some cases, all zeros) in the host portion of the
forwarding destination IP address. When a router forwards such
a broadcast, it sends a copy of the packet out each of
its enabled IP interfaces.
Note: You also can enable or disable this parameter
on an individual interface basis. See Table 15.2 on
page 15-14.
Directed The packet format the router treats as a directed
broadcast mode broadcast. The following formats can be directed
broadcast:
• All ones in the host portion of the packet's
destination address.
• All zeroes in the host portion of the packet's
destination address.
Source-routed A source-routed packet contains a list of IP addresses
packet through which the packet must pass to reach its
forwarding destination.
ICMP Router An IP protocol a router can use to advertise the IP
Discovery addresses of its router interfaces to directly attached
Protocol (IRDP) hosts. You can enable or disable the protocol, and
change the following protocol parameters:
• Forwarding method (broadcast or multicast)
• Hold time
• Maximum advertisement interval
• Minimum advertisement interval
• Router preference level
Note: You also can enable or disable IRDP and
configure the parameters on an individual interface
basis. See Table 15.2 on page 15-14.
Reverse ARP A IP mechanism a host can use to request an IP
(RARP) address from a directly attached router when the host
boots.
Static RARP An IP address you place in the RARP table for RARP
entries requests from hosts.
Note: You must enter the RARP entries manually.
The Layer 3 Switch does not have a mechanism for
learning or dynamically generating RARP entries.
December 2000
Configuring IP
Default See page...
64 hops 15-35
Disabled 15-35
All ones 15-37
Note: If you enable
all-zeroes directed
broadcasts, all-ones
directed broadcasts
remain enabled.
Enabled 15-36
Disabled 15-66
Enabled 15-68
No entries 15-69
15 - 11