3Com Router User Manual

Configure RIP 417
RIP Version 2 does not have provisions for a zero field in its header so this 
configuration is invalid for RIP-2.
Perform the following configurations in RIP view.
Ta b l e 473   Configure Check Zero Field of RIP Version 1
RIP VERSION 1 enables zero field check by default.
Specifying the Status of 
an InterfaceYou can specify the working status of RIP on an interface, such as whether RIP is 
running on the interface and whether updated messages are transmitted or 
received on the...

418CHAPTER 28: CONFIGURING RIP
By default, the router is enabled to receive the host routes.
Enabling Route 
Summarization for RIP 
Version 2Route summarization summarizes the routes of different subnets within the same 
natural network segment and sends the summary to other network segments as a 
summarized route with a natural mask. Route summarization largely reduces the 
network expenditure and the routing table size.
RIP-1 always sends routes with natural mask. RIP-2 supports sub-net mask and 
routs...

Configure RIP 419
Configuring RIP 
Horizontal 
Segmentation on the 
InterfaceRIP is a Distance-Vector algorithm routing protocol. It uses the split-horizon 
algorithm to avoid loop routes. Split-horizon means that routes received at a 
certain interface are not sent to the same interface. If correct transmission of 
routes is more important than efficiency, then split-horizon should be disabled.
Disabling split-horizon mechanism is not effective on point-to-point connection 
links. 
Perform the following...

420CHAPTER 28: CONFIGURING RIP
Since the route metric of route import cannot be reverted, the dynamic route 
information may be significantly distorted. Therefore, route import is done 
cautiously to prevent loss of RIP protocols performance.
Specifying Additional 
Route Metric Values for 
RIPThe additional routing metric here is to add input or output metric for routes 
obtained for RIP. The
 rip metricin will add a designated metric value while 
receiving routes on the interface, then add this route...

Displaying and Debugging RIP 421
Configure filtering the routing information being advertised
Ta b l e 484   Filter the Routing Information Being Advertised by RIP
By default, RIP does not filter any route information received or being advertised.
The protocol attribute specifies the routing domain that can be filtered. At 
present, RIP can filter routes domain such as Connected, Static, OSPF, OSPF-ASE 
and BGP. See “Configure Route Filter” of “Configuration of IP Routing Policy” for 
details.
Resetting...

422CHAPTER 28: CONFIGURING RIP
RIP - Unicast 
Configuration 
ExampleRIP is a broadcast protocol so it can only exchange routing information with 
non-broadcasting networks in unicast mode. This example shows how to 
configure RIP message unicasting.
Router A connects Router B and Router C with serial lines in non-broadcasting 
networks. Router A (192.1.1.2) only wants to send the routing updating 
information to the adjacent Router B (192.1.1.2) without sending the information 
to Router C.
Figure 145...

29
CONFIGURING OSPF
This chapter covers the following topics:
■OSPF Overview
■Configuring OSPF
■Displaying and Debugging OSPF
■OSPF Configuration Example
OSPF OverviewOpen Shortest Path First (OSPF) is an autonomous, link-state-based internal 
routing protocol developed by Internet Engineering Task Force (IETF). The current 
version is version 2 (RFC1583), which features the following: 
■Applicable range — Supports networks of various sizes and hundreds of 
routers.
■Fast convergence — Sends an update...

424CHAPTER 29: CONFIGURING OSPF
0.0.0.0. All areas must be continuous logically. Thus, a virtual link is introduced to 
the backbone to ensure that physically separated areas are still connected logically. 
The router between the ASs is called autonomous system boundary router (ASBR). 
Routing information, such as static routing, RIP routing, BGP routing, outside the 
OSPF AS can be learned from the ASBR.
Computation of the OSPF protocol is summarized as follows:
1Every router supporting OSPF maintains a...

Configuring OSPF425
■Configuring Sending Packet Cost
■Configuring a Peer for the NBMA Interface
■Specifying the Router Priority
■Specifying the Hello Interval
■Specifying the Dead Interval
■Specifying the Retransmitting Interval
■Specifying the Transmit-delay
■Configuring a Stubby Area and a Totally Stubby Area
■Configuring an NSSA Area
■Configuring Route Summarization within the OSPF Domain.
■Creating and Configuring a Virtual Link
■Configuring Authentication
■Configuring Route Import for OSPF...

426CHAPTER 29: CONFIGURING OSPF
By default, OSPF is disabled.
Associating an Area-id 
with the Specified 
InterfaceThe OSPF protocol divides the autonomous system into areas. An area is the 
logical group of the router. Some routers belong to different areas (called area 
boundary router ABR), while a network segment can only be in one area. In other 
words, each interface running the OSPF protocol must be put in a specific area. 
The area is flagged with an area ID. The ABR transmits routing information...