Module 5 –Operating a Network Using Multiple Routing Protocols doc

© 2008 Cisco Systems, Inc. All rights reserved. Cisco ConfidentialBSCI
1
Route Optimization
BSCI Module 5 – Lesson 1 Operating a Network Using
Multiple Routing Protocols
© 2008 Cisco Systems, Inc. All rights reserved.BSCI
2
CCNP – BSCI Bachkhoa Networking Academy
Học viện mạng Bách Khoa - www.bkacad.com
Objectives
 Using Multiple Routing Protocols
 Defining Route Redistribution
 Redistributing Route Information
 Using Seed Metrics
 Seed Metrics Example
 Defining Administrative Distance
 Modifying Administrative Distances
© 2008 Cisco Systems, Inc. All rights reserved.BSCI
3
CCNP – BSCI Bachkhoa Networking Academy
Học viện mạng Bách Khoa - www.bkacad.com
Objectives
 Explain the purpose and use of seed metrics in route
redistribution.
 Describe how to redistribute routes into RIP, OSPF,
EIGRP, and IS-IS.
 Explain how to verify route redistribution.
 Explain how to control routing updates using the
passive-interface default command and route
maps.
 Describe new DHCP commands.

© 2008 Cisco Systems, Inc. All rights reserved.BSCI
4
CCNP – BSCI Bachkhoa Networking Academy
Học viện mạng Bách Khoa - www.bkacad.com
Purpose of this Lesson
 Coverage of topics new to the “Route Optimization”
module of BSCI.
 What’s new in this module?
–Detailed explanation of seed metrics
–Redistribute routes into RIP, OSPF, EIGRP, and IS-IS
–Verify route redistribution
–Controlling routing updates with the passive-interface default
command and route maps
–Using the distance command to avoid suboptimal routing
–More DHCP commands
© 2006 Cisco Systems, Inc. All rights reserved. Cisco PublicBSCI Module 3
5
Seed Metrics and
Route
Redistribution
© 2008 Cisco Systems, Inc. All rights reserved.BSCI
6
CCNP – BSCI Bachkhoa Networking Academy
Học viện mạng Bách Khoa - www.bkacad.com
Using Multiple IP Routing Protocols
•Company mergers,
multiple departments
managed by multiple
network administrators,
multivendor

environments
© 2008 Cisco Systems, Inc. All rights reserved.BSCI
7
CCNP – BSCI Bachkhoa Networking Academy
Học viện mạng Bách Khoa - www.bkacad.com
Using Multiple Routing Protocols
 Here we see a list of the most common reasons to use multiple
routing protocols:
1. As an interim solution as you are migrating from an older Interior
Gateway Protocol (IGP) to a new IGP
2. You may have to use an older routing protocol in some host
systems: for example, UNIX host-based routers running RIP.
3. Different departments might not want to upgrade their routers to
support a new routing protocol.
4. In a mixed-vendor environment, you can use a routing protocol
specific to Cisco such as EIGRP in the Cisco portion of the
network and a common standards-based routing protocol, like
OSPF, to communicate with devices from other vendors.
© 2008 Cisco Systems, Inc. All rights reserved.BSCI
8
CCNP – BSCI Bachkhoa Networking Academy
Học viện mạng Bách Khoa - www.bkacad.com
Redistributing Route Information
 Factors that have the most impact on redistribution include:
–Metrics
–Administrative distance
–Classful/classless capabilities of the protocols
 These factors will be discussed in various sections of this module.
© 2008 Cisco Systems, Inc. All rights reserved.BSCI
9

CCNP – BSCI Bachkhoa Networking Academy
Học viện mạng Bách Khoa - www.bkacad.com
Redistribution with Seed Metric
© 2008 Cisco Systems, Inc. All rights reserved.BSCI
10
CCNP – BSCI Bachkhoa Networking Academy
Học viện mạng Bách Khoa - www.bkacad.com
Default Seed Metrics
Protocol Default Seed Metrics
RIP Infinity
IGRP/EIGRP Infinity
OSPF 20 for all except BGP, which is 1
IS-IS 0
BGP BGP metric is set to IGP metric value
© 2008 Cisco Systems, Inc. All rights reserved.BSCI
11
CCNP – BSCI Bachkhoa Networking Academy
Học viện mạng Bách Khoa - www.bkacad.com
AD
© 2008 Cisco Systems, Inc. All rights reserved.BSCI
12
CCNP – BSCI Bachkhoa Networking Academy
Học viện mạng Bách Khoa - www.bkacad.com
Prefix length
 192.168.32.1
 192.168.32.100
© 2008 Cisco Systems, Inc. All rights reserved.BSCI
13
CCNP – BSCI Bachkhoa Networking Academy
Học viện mạng Bách Khoa - www.bkacad.com

Modifying Administrative Distances
Source router supplying the routing information
Distace bgp
© 2008 Cisco Systems, Inc. All rights reserved.BSCI
14
CCNP – BSCI Bachkhoa Networking Academy
Học viện mạng Bách Khoa - www.bkacad.com
Self Check
1. How is a seed metric used in redistribution?
2. What does a metric of infinity tell the router?
3. Which routing protocols should be configured with
default metrics to prevent the default of infinity?
© 2006 Cisco Systems, Inc. All rights reserved. Cisco PublicBSCI Module 3
15
Configuring and
Verifying Route
Redistribution
© 2008 Cisco Systems, Inc. All rights reserved.BSCI
16
CCNP – BSCI Bachkhoa Networking Academy
Học viện mạng Bách Khoa - www.bkacad.com
Redistribution Supports All Protocols
RtrA(config)#router rip
RtrA(config-router)#redistribute ?
bgp Border Gateway Protocol (BGP)
connected Connected
eigrp Enhanced Interior Gateway Routing Protocol (EIGRP)
isis ISO IS-IS
iso-igrp IGRP for OSI networks
metric Metric for redistributed routes

mobile Mobile routes
odr On Demand stub Routes
ospf Open Shortest Path First (OSPF)
rip Routing Information Protocol (RIP)
route-map Route map reference
static Static routes
<cr>
© 2008 Cisco Systems, Inc. All rights reserved.BSCI
17
CCNP – BSCI Bachkhoa Networking Academy
Học viện mạng Bách Khoa - www.bkacad.com
2 way , 1 way redistribution
© 2008 Cisco Systems, Inc. All rights reserved.BSCI
18
CCNP – BSCI Bachkhoa Networking Academy
Học viện mạng Bách Khoa - www.bkacad.com
Planning Redistribution
 Locate the boundary router between two routing processes.
 Determine which routing process is the core or backbone
process
 Determine which routing process is the edge or migration
process
 Select a method for injecting the required edge protocol
routes into the core.
© 2008 Cisco Systems, Inc. All rights reserved.BSCI
19
CCNP – BSCI Bachkhoa Networking Academy
Học viện mạng Bách Khoa - www.bkacad.com
 Use this command to redistribute routes into RIP:
–Router(config-router)# redistribute protocol

[process-id] [match route-type] [metric metric-
value] [route-map map-tag]
Configuring Redistribution into RIP
RtrA(config)# router rip
RtrA(config-router)# redistribute ospf ?
<1-65535> Process ID
RtrA(config-router)# redistribute ospf 1 ?
match Redistribution of OSPF routes
metric Metric for redistributed routes
route-map Route map reference
…
<cr>
 Default metric is infinity.
© 2008 Cisco Systems, Inc. All rights reserved.BSCI
20
CCNP – BSCI Bachkhoa Networking Academy
Học viện mạng Bách Khoa - www.bkacad.com
The redistribute command parameters for RIP
Parameter Description
protocol
Source protocol from which routes are being redistributed.
process-id
This value is an AS number. For OSPF, this value is an OSPF
process ID.
match route-type
(Optional) Command parameter used for redistributing OSPF
routes into another routing protocol. For OSPF, the criterion by
which OSPF routes are redistributed into other routing domains.
metric metric-
value

(Optional) Parameter used to specify the RIP seed metric for the
redistributed route. When you are redistributing into RIP, this
value is not specified and no value is specified using the default-
metric router configuration command, then the default metric is
0, which is interpreted as infinity, and routes will not be
redistributed. The metric for RIP is the hop count.
route-map map-
tag
(Optional) Identifier of a configured route map to be interrogated
to filter the importation of routes from this source routing protocol
to the current routing protocol.
© 2008 Cisco Systems, Inc. All rights reserved.BSCI
21
CCNP – BSCI Bachkhoa Networking Academy
Học viện mạng Bách Khoa - www.bkacad.com
Redistributing from Classless to Classful Protocols
 OSPF Has a Longer Mask Than RIP
ip route 128.103.35.0 255.255.255.0 null0
router rip
redistribute static
default metric 1
© 2008 Cisco Systems, Inc. All rights reserved.BSCI
22
CCNP – BSCI Bachkhoa Networking Academy
Học viện mạng Bách Khoa - www.bkacad.com
Redistributing from Classless to Classful Protocols
 RIP Has a Longer Mask Than OSPF
ip route 128.103.35.32 255.255.255.248 E0/0
ip route 128.103.35.40 255.255.255.248 E0/0
ip route 128.103.35.16 255.255.255.248 E1/0

ip route 128.103.35.24 255.255.255.248 E1/0
ip route 128.103.35.64 255.255.255.248
128.103.35.34
ip route 128.103.35.64 255.255.255.248
128.103.35.18
ip route 128.103.35.72 255.255.255.248
128.103.35.34
ip route 128.103.35.72 255.255.255.248
128.103.35.18
router rip
redistribute static
default metric 1
© 2008 Cisco Systems, Inc. All rights reserved.BSCI
23
CCNP – BSCI Bachkhoa Networking Academy
Học viện mạng Bách Khoa - www.bkacad.com
Redistributing into RIP
© 2008 Cisco Systems, Inc. All rights reserved.BSCI
24
CCNP – BSCI Bachkhoa Networking Academy
Học viện mạng Bách Khoa - www.bkacad.com
Configuring Redistribution into OSPF
 Use this command to redistribute routes into OSPF:
–Router(config-router)# redistribute protocol
[process-id] [metric metric-value] [metric-type
type-value] [route-map map-tag] [subnets] [tag
tag-value]
 Default metric is 20.
 Default metric type is 2.
 Subnets do not redistribute by default.

© 2008 Cisco Systems, Inc. All rights reserved.BSCI
25
CCNP – BSCI Bachkhoa Networking Academy
Học viện mạng Bách Khoa - www.bkacad.com
Example: Redistribution into OSPF
RtrA(config)# router ospf 1
RtrA(config-router)# redistribute eigrp ?
<1-65535> Autonomous system number
RtrA(config-router)# redistribute eigrp 100 ?
metric Metric for redistributed routes
metric-type OSPF/IS-IS exterior metric type for
redistributed routes
route-map Route map reference
subnets Consider subnets for redistribution into OSPF
tag Set tag for routes redistributed into OSPF
…
<cr>