Configuring Static
Routes
Router(config)# ip
route prefix mask {ip-address | interface-type interface-number [ip-address]}
[distance] [name] [permanent | track number] [tag tag]
Specifying a
Default Network
If a router has a
directly connected interface onto the specified default network, the dynamic
routing protocols running on that device will generate or source a default route.
In the case of RIP, the router will advertise the pseudonetwork 0.0.0.0. In the
case of EIGRP, the network itself is advertised and flagged as an external
route.
Router(config)# ip
default-network network-number
Changing the
Maximum Number of Paths
Most IP routing
protocols install a maximum of four parallel routes in a routing table. Static
routes always install six routes. The exception is BGP, which by default allows
only one path (the best path) to a destination.
In router
configuration mode:
Router(config-router)#
maximum-paths number-paths
Preventing Routing
Updates Through an Interface
You can keep routing
update messages from being sent through a router interface.
In OSPF, the passive
interface appears as a stub network. OSPF routing information
is neither sent nor received.
In IS-IS, the
specified IP addresses are advertised without actually running IS-IS on those
interfaces.
Router(config-router)#
passive-interface interface-type interface-number
To set all interfaces
as passive by default:
Router(config-router)#
passive-interface default
Controlling the
Advertising of Routes in Routing Updates
Suppress routes from being advertised in routing updates using:
Router(config-router)# distribute-list {access-list-number | access-list-name}
out [interface-name | routing-process | as-number]
OSPF: cannot specify an interface name, applies only to external routes
(E1, E2).
Controlling the
Processing of Routing Updates
To avoid processing certain routes listed in incoming updates.
Router(config-router)# distribute-list {access-list-number | access-list-name}
in [interface-type interface-number]
Does not apply to OSPF or IS-IS.
Filtering Sources
of Routing Information
Router(config-router)# distance ip-address wildcard- mask [ip-standard-acl
| ip-extended-acl | access-list-name]
Enabling
Policy-Based Routing
Router(config-if)# ip policy route-map map-tag
Define the criteria by which packets are examined:
Router(config)# route-map map-tag [permit | deny] [sequence-number]
Router(config-route-map)# match length minimum-length
maximum-length
Router(config-route-map)# match ip address {access-list-number | access-list-name}
[access-list-number | access-list-name]
To set the precedence and specify where the packets (that pass) are
output:
Router(config-route-map)# set ip precedence {number | name}
Router(config-route-map)# set ip next-hop ip-address [ip-address]
Router(config-route-map)# set interface interface-type
interface-number [... interface-type interface-number]
Router(config-route-map)# set ip default next-hop ip-address [ip-address]
Router(config-route-map)# set default interface interface-type
interface-number [... interface-type interface-number
The set ip next-hop and set ip default next-hop commands
are similar but have a different order of operation:
- Configuring the set ip next-hop command causes the system to use policy routing first and then use the routing table.
- Configuring the set ip default next-hop causes the system to use the routing table first and then policy-route the specified next hop.
To display the cache entries in the policy route cache, use the show
ip cache policy command.
Enabling
Fast-Switched Policy Routing
Fast-switched policy routing supports all of the match commands
and most of the set commands, except for the following restrictions:
The set ip default
command is not supported.
The set interface
command is supported only over point-to-point links
Router(config-if)# ip route-cache policy
Enabling Local
Policy Routing
All packets originating on the router will then be subject to local
policy routing.
Router(config)# ip local policy route-map map-tag
QoS Policy
Propagation via BGP Configuration
Configuring QoS
Policy Propagation Based on Community Lists
Router(config)# route-map route-map-name [permit | deny [sequence-number]]
Router(config-route-map)# match community-list community-list-number
[exact]
Router(config-route-map)# set ip precedence [number | name]
Router(config-route-map)# exit
Router(config)# router bgp autonomous-system
Router(config-router)# table-map route-map-name
Router(config-router)# ip community-list community-list-number {permit
| deny} community-number
Router(config-router)# exit
Router(config)# interface interface-type interface-number
Router(config-if)# bgp-policy {source | destination}
ip-prec-map
Configuring QoS
Policy Propagation Based on the Autonomous System Path Attribute
Router(config)# route-map route-map-name [permit | deny [sequence-number]]
Router(config-route-map)# match as-path path-list-number
Router(config-route-map)# set ip precedence [number | name]
Router(config-route-map)# exit
Router(config)# router bgp autonomous-system
Router(config-router)# table-map route-map-name
Router(config-router)# ip as-path access-list access-list-number
{permit | deny} as-regular-expression
Router(config-router)# exit
Router(config)# interface interface-type interface-number
Router(config-if)# bgp-policy {source | destination}
ip-prec-map
Configuring QoS
Policy Propagation Based on an Access List - INCOMPLETE
Router(config)# route-map route-map-name [permit | deny [sequence-number]]
Router(config-route-map)# match ip address access-list-number
Router(config-route-map)# set ip precedence [number | name]
Router(config-route-map)# exit
Router(config)# router bgp autonomous-system
Router(config-router)# table-map route-map-name
Router(config-router)# exit
Router(config)# access-list access-list-number {permit | deny}
source
Router(config)# interface interface-type interface-number
Table-map: Modifies the metric and tag values when the IP routing table
is updated with BGP learned routes.
Examples:
Router A learns routes from autonomous system 10 and autonomous system
60. QoS policy is applied to all packets that match the defined route maps. Any
packets from Router A to autonomous system 10 or autonomous system 60 are sent
the appropriate QoS policy, as the numbered steps indicate.
Managing
Authentication Keys
Router(config)# key chain name-of-chain
Router(config-keychain)# key number
Router(config-keychain-key)# key-string text
Router(config-keychain-key)# accept-lifetime start-time {infinite
| end-time | duration seconds}
Specifies the time period during which the key can be received.
Router(config-keychain-key)# send-lifetime start-time {infinite
| end-time | duration seconds}
Specifies the time period during which the key can be sent.
Examples:
Router(config)# key chain trees
Router(config-keychain)# key 1
Router(config-keychain-key)# key-string willow
Router(config-keychain-key)# key
2
Router(config-keychain-key)# key-string
chestnut
Router(config-keychain-key)# accept-lifetime
00:00:00 Dec 5 2004 23:59:59 Dec 5 2005
Router(config-keychain-key)# send-lifetime
06:00:00 Dec 5 2004 18:00:00 Dec 5 2005
Router(config-keychain-key)# exit
Router(config-keychain)# exit
