User`s guide

XSR User’s Guide 81
Chapter 5 IP Routing Protocols
Configuring IP
OSPF is superior to RIP because as a link-state protocol, it converges faster
than RIP, a distance-vector protocol; OSPF’s longest path is not limited as is
RIP’s (to 15); OSPF supports subnets - a subnet mask is associated with each
advertised route. The XSR’s implementation of OSPF permits static route
distribution only and is limited by the size of installed memory for the
following functionality:
 Total route ceiling
 Total AS external (types 5 and 7)
 Total LSA types 1 to 4
CAUTION
Your router must be installed within the network in such a way that the
above limits are not exceeded.
NOTE
OSPF does not learn neighbors over unnumbered WAN interfaces with
Firewall functionality enabled.
OSPF is supported on the XSR by the following features:
 Set globally with the
router ospf and per port with the network
<ip address> area
commands: they support OSPF on LAN and
WAN interfaces with these defaults: no authentication, cost 10 (LAN)
or Serial (64), dead interval of 40 seconds, hello interval of 10 seconds,
priority 1, and 5-second retransmit interval.
 Intra- and inter-area, and Type 1 and 2 external routing
 Broadcast, point-to-point and point to multi-point models
 Protocol enabled/disabled with the
router ospf command
 Area IDs identified and defined with the
network command
 Address ranges used by ABRs defined by
area range command
 OSPF priority with the
ip ospf priority command
 Cost to send a packet over interface with
ip ospf cost command