- mac-list
- match as-number
- match as-path
- match community
- match extcommunity
- match interface
- match ip address
- match ip multicast
- match ip next-hop prefix-list
- match ip route-source prefix-list
- match metric
- match mac-list
- match route-type
- match tag
- match vlan
- maxas-limit
- maximum-paths (BGP)
- maximum-prefix
M Commands
This chapter describes the Cisco NX-OS Border Gateway Protocol (BGP) commands that begin with M.
mac-list
To filter based on a MAC address, use the mac-list command. To remove the MAC list entry, use the no form of this command.
mac-list name [seq number] {permit | deny} mac-address [mac-mask]
no mac-list name [seq number] {permit | deny} mac-address [mac-mask]
Syntax Description
Command Default
No match values are defined.
Command Modes
Global configuration mode
Command History
|
|
|
|---|---|
6.0(2)N1(1) |
This command was introduced. |
Usage Guidelines
You can match against the MAC list in a route map.
Examples
This example shows how to create the Red MAC list:
switch(config)# mac-list Red seq 1 permit 0022.5579.a4c1 ffff.ffff.0000
Related Commands
|
|
|
|---|---|
match mac-list |
Matches a MAC address in a MAC list. |
show mac-list |
Displays information about a MAC list. |
match as-number
To match to a Border Gateway Protocol (BGP ) autonomous system (AS) number, use the match as-number command. To remove an AS number list entry, use the no form of this command.
match as-number {number [,number...] | as-path-access-list name [...name]}
no match as-number {number [,number...] | as-path-access-list name [...name]}]
Syntax Description
Command Default
None
Command Modes
Route-map configuration mode
Command History
|
|
|
|---|---|
6.0(2)N1(1) |
This command was introduced. |
Command History
Usage Guidelines
Use the match as-number command to provide a list of AS numbers or an AS-path access list using a regular expression. BGP uses this match criteria to determine which BGP peers to create a BGP session with.
Use the route map to specify a range of AS numbers whose peers can establish a session with the local BGP through prefix peering. Cisco NX-OS ignores any other match commands if the match as-number command is present in the route map.
Examples
This example shows how to configure a list of AS numbers:
switch(config)# route-map IGP2BGP
switch(config-route-map)# match as-number 64496, 64498-64510
Related Commands
|
|
|
|---|---|
ip as-path access-list |
Creates an AS-path list. |
neighbor |
Configures BGP peers. |
route-map |
Defines the conditions for redistributing routes from one routing protocol into another. |
match as-path
To match a Border Gateway Protocol (BGP) autonomous system (AS) path access list, use the match as-path command. To remove a path list entry, use the no form of this command.
match as-path name [...name]
no match as-path name [...name]
Syntax Description
Command Default
No path lists are defined.
Command Modes
Route-map configuration mode
Command History
|
|
|
|---|---|
6.0(2)N1(1) |
This command was introduced. |
Usage Guidelines
The values set by the match as-path command overrides global values.
A route map can have several parts. Any route that does not match at least one match clause relating to a route-map command is ignored; that is, the route is not advertised for outbound route maps and is not accepted for inbound route maps. If you want to modify some particular data, you must configure a second route-map section with an explicit match specified.
Examples
This example sets the autonomous system path to match BGP autonomous system path access list 20:
switch(config)# route-map IGP2BGP
switch(config-route-map)# match as-path 20
switch(config-route-map)#
Related Commands
match community
To match a Border Gateway Protocol (BGP) community, use the match community command. To remove the match community command from the configuration file and restore the system to its default condition where the software removes the BGP community list entry, use the no form of this command.
match community name [...name] [exact-match]
no match community name [...name] [exact-match]
Syntax Description
Command Default
No community list is matched by the route map.
Command Modes
Route-map configuration mode
Command History
|
|
|
|---|---|
6.0(2)N1(1) |
This command was introduced. |
Usage Guidelines
A route map can have several parts. Any route that does not match at least one match command that is related to a route-map command is ignored; that is, the route is not advertised for outbound route maps and is not accepted for inbound route maps. If you want to modify some particular data, you must configure a second route-map section with an explicit match specified.
Matching that is based on the community list number is one of the types of match commands applicable to BGP.
Examples
This example shows how to match two BGP communities:
switch(config)# route-map test2
switch(config-route-map)# match community bgpLow bgpHigh
This example shows that the routes that match community list 1 have the weight set to 200. Any route that has the standard community 109 only has the weight set to 200.
switch(config)# ip community-list standard bgpLow permit 109
switch(config)# route-map set_weight
switch(config-route-map)# match community bgpLow exact-match
switch(config-route-map)# set weight 200
This example shows the routes that match the community list 500. Any route that has expanded community 1 have the weight set to 150.
switch(config)# ip community-list expanded 500 permit [0-9]*
switch(config)# route-map MAP_NAME permit 10
switch(config-route-map)# match community 500
switch(config-route-map)# set weight 150
Related Commands
match extcommunity
To match a Border Gateway Protocol (BGP) extended community in a route map, use the match extcommunity command. To remove the match from the route map, use the no form of this command.
match extcommunity name [...name] [exact-match]
no match extommunity name [...name] [exact-match]
Syntax Description]
Command Default
No community list is matched by the route map.
Command Modes
Route-map configuration mode
Command History
|
|
|
|---|---|
6.0(2)N1(1) |
This command was introduced. |
Usage Guidelines
A route map can have several parts. Any route that does not match at least one match command in the route map is ignored; that is, the route is not advertised for outbound route maps and is not accepted for inbound route maps. If you want to modify some particular data, you must configure a second route-map section with an explicit match specified.
Matching that is based on the extended community list number is one of the types of match commands applicable to BGP.
Examples
This example shows how to match two BGP extended community lists:
switch(config)# route-map test2
switch(config-route-map)# match extcommunity bgpLocal bgpRemote
This example shows that the routes that match the extended community list bgpLocal change from nontransitive to transitive:
switch(config)# ip extcommunity-list standard bgpLocal permit generic nontransitive 1.9
switch(config)# route-map deletCommunity
switch(config-route-map)# match extcommunity bgpLocal exact-match
switch(config-route-map)# set extcommunity generic transitive 1.9
Related Commands
match interface
To match an interface in a route map, use the match interface command. To remove the match, use the no form of this command.
match interface {interface-type number [, interface-type number...]}
no match interface {interface-type number [, interface-type number...]}
Syntax Description
interface-type |
Interface type. Use ? to see a list of supported interfaces. |
number |
(Optional) Interface number. Use ? to see the range. |
Command Default
None
Command Modes
Route-map configuration mode
Command History
|
|
|
|---|---|
6.0(2)N1(1) |
This command was introduced. |
Usage Guidelines
Route next-hop addresses that are reached by one of the interfaces result in a match for the route map.
A route map can have several parts. Any route that does not match at least one match clause that relates to a route-map command is ignored; that is, the route is not advertised for outbound route maps and is not accepted for inbound route maps. If you want to modify some particular data, you must configure a second route-map section with an explicit match specified.
Examples
This example shows how to configure a list of interfaces:
switch(config)# route-map test1
switch(config-route-map)# match interface ethernet 2/1, ethernet 4/3
Related Commands
|
|
|
|---|---|
route-map |
Defines the conditions for redistributing routes from one routing protocol into another. |
match ip address
To distribute any routes that have a destination IP network number address that is permitted by a standard access list, an expanded access list, or a prefix list, use the match ip address command. To remove the match ip address entry, use the no form of this command.
match ip address {prefix-list prefix-list-name [prefix-list-name...]}
no match ip address {prefix-list prefix-list-name [prefix-list-name...]}
Syntax Description
Command Default
No prefix lists are specified.
Command Modes
Route-map configuration mode
Command History
|
|
|
|---|---|
6.0(2)N1(1) |
This command was introduced. |
Usage Guidelines
An ellipsis (...) in the command syntax indicates that your command input can include multiple values for the prefix-list-name argument.
Like matches in the same route map subblock are filtered with "or" semantics. If any one match clause is matched in the entire route map subblock, this match is treated as a successful match. Dissimilar match clauses are filtered with "and" semantics, so dissimilar matches are filtered logically. If the first set of conditions is not met, the second match clause is filtered. This process continues until a match occurs or there are no more match clauses.
Use route maps to redistribute routes.
Use the route-map global configuration command and the match and set route-map configuration commands to define the conditions for redistributing routes from one routing protocol into another. Each route-map command has a list of match and set commands associated with it. The match commands specify the match criteria—the conditions under which redistribution is allowed for the current route-map command. The set commands specify the set actions—the particular redistribution actions to perform if the criteria enforced by the match commands are met. The no route-map command deletes the route map.
The match route-map configuration command has multiple formats. The match commands can be given in any order, and all match commands must pass to cause the route to be redistributed according to the set actions given with the set commands. The no forms of the match commands remove the specified match criteria.
When you are passing routes through a route map, a route map can have several sections that contain specific match clauses. Any route that does not match at least one match clause that relates to a route-map command is ignored; that is, the route is not advertised for outbound route maps and is not accepted for inbound route maps. If you want to modify some particular data, you must configure a second route map section with an explicit match specified.
Examples
This example shows how to match routes that have addresses specified by an access list test:
switch(config)# interface ethernet 2/10
switch(config-if)# no switchport
switch(config-if)# exit
switch(config)# route-map chicago
switch(config-route-map)# match ip address test
Related Commands
match ip multicast
To configure the IPv4 multicast features for the route-map matching, use the match ip multicast command. To remove the match, use the no form of this command.
match ip multicast {group address/length | source address/length | rp address/length [rp-type asm]}
no match ip multicast
Syntax Description
Command Default
None
Command Modes
Route-map configuration mode
Command History
|
|
|
|---|---|
6.0(2)N1(1) |
This command was introduced. |
Usage Guidelines
The match ip multicast command is the only match command that is evaluated in the route map. You can specify the group prefix, group range, and source prefix to filter messages with the match ip multicast command.
Use the route-map command to enter route-map configuration mode. Once you enter the route-map command, the prompt changes to the following:
switch(config-route-map)#
Once you enter route-map configuration mode, you can enter the match ip multicast command.
You can configure both group and rp options.
Examples
This example shows how to specify the group IPv4 prefix and the length of the IPv4 prefix for the neighbors to match:
switch(config)# route-map blueberry
switch(config-route-map)# match ip multicast group 192.0.0.0/19
switch(config-route-map)#
This example shows how to specify both the group IPv4 prefix and the rendezvous point of the IPv4 prefix for the neighbors to match:
switch(config)# route-map raspberry
switch(config-route-map)# match ip multicast group 192.0.0.0/19 rp 209.165.201.0/27
switch(config-route-map)#
Related Commands
match ip next-hop prefix-list
To redistribute any IPv4 routes that have a next-hop router address passed by one of the access lists specified, use the match ip next-hop prefix-list command. To remove the next hop entry, use the no form of this command.
match ip next-hop prefix-list prefix-list-name [ ...prefix-list-name]
no match ip next-hop prefix-list prefix-list-name [ ...prefix-list-name]
Syntax Description
prefix-list-name |
Number or name of a prefix list. It can be any alphanumeric string up to 63 characters. The ellipsis indicates that multiple values can be entered, up to 32 prefix lists. |
Command Default
Routes are distributed freely, without being required to match a next hop address.
Command Modes
Route-map configuration mode
Command History
|
|
|
|---|---|
6.0(2)N1(1) |
This command was introduced. |
Command History
Usage Guidelines
An ellipsis (...) in the command syntax indicates that your command input can include multiple values for the prefix-list-name argument.
Use the route-map global configuration command, and the match and set route-map configuration commands to define the conditions for redistributing routes from one routing protocol into another. Each route-map command has a list of match and set commands associated with it. The match commands specify the match criteria—the conditions under which redistribution is allowed for the current route-map command. The set commands specify the set actions—the particular redistribution actions to perform if the criteria enforced by the match commands are met. The no route-map command deletes the route map.
The match route-map configuration command has multiple formats. The match commands can be given in any order and all match commands must pass to cause the route to be redistributed according to the set actions given with the set commands. The no forms of the match commands remove the specified match criteria.
When you are passing routes through a route map, a route map can have several parts. Any route that does not match at least one match clause that relates to a route-map command is ignored; that is, the route is not advertised for outbound route maps and is not accepted for inbound route maps. If you want to modify some particular data, you must configure a second route map section with an explicit match specified.
Examples
This example shows how to distributes routes that have a next-hop router address passed by the prefix list test:
switch(config)# route-map blue
switch(config-route-map)# match ip next-hop prefix-list test
switch(config-route-map)#
Related Commands
match ip route-source prefix-list
To redistribute IPv4 routes that have been advertised by routers and access servers at the address specified by the access lists, use the match ip route-source prefix-list command. To remove the route-source entry, use the no form of this command.
match ip route-source prefix-list prefix-list-name [ ...prefix-list-name]
no match ip route-source prefix-list prefix-list-name [ ...prefix-list-name]
Syntax Description
prefix-list-name |
Number or name of a prefix list. It can be any alphanumeric string up to 63 characters. The ellipsis indicates that multiple values can be entered, up to 32 prefix lists. |
Command Default
No filtering on route source.
Command Modes
Route-map mode
Command History
|
|
|
|---|---|
6.0(2)N1(1) |
This command was introduced. |
Usage Guidelines
An ellipsis (...) in the command syntax indicates that your command input can include multiple values for the prefix-list-name argument.
Use the route-map global configuration command, and the match and set route-map configuration commands to define the conditions for redistributing routes from one routing protocol into another. Each route-map command has a list of match and set commands associated with it. The match commands specify the match criteria—the conditions under which redistribution is allowed for the current route-map command. The set commands specify the set actions—the particular redistribution actions to perform if the criteria enforced by the match commands are met. The no route-map command deletes the route map.
The match route-map configuration command has multiple formats. The match commands can be given in any order, and all match commands must pass to cause the route to be redistributed according to the set actions given with the set commands. The no forms of the match commands remove the specified match criteria.
A route map can have several parts. Any route that does not match at least one match clause that relates to a route-map command is ignored; that is, the route is not advertised for outbound route maps and is not accepted for inbound route maps. If you want to modify only some data, you must configure second route map section with an explicit match specified.
There are situations in which the next hop and source router address of the route are not the same.
Examples
This example shows how to distribute routes that have been advertised by routers and access servers at the addresses specified by access lists 5 and 80:
switch(config)# route-map blue
switch(config-route-map)# match ip route-source prefix-list 5 80
Related Commands
match metric
To redistribute routes in the routing table that match the routing metric value, use the match metric command. To remove the tag entry, use the no form of this command.
match metric metric-value [+- deviation-number] [...metric-value [+- deviation-number]]
no match metric metric-value [+- deviation-number] [...metric-value [+- deviation-number]]
Syntax Description
Command Default
No match values are defined.
Command Modes
Route-map configuration mode
Command History
|
|
|
|---|---|
6.0(2)N1(1) |
This command was introduced. |
Usage Guidelines
To redistribute routes with the specified metric, use the match metric command in route-map configuration mode. To remove the entry for the redistributed route from the routing table, use the no form of this command.
You can specify one or more metrics (or) range of metrics using the deviation-number argument. At least one of the specified metrics must match for the command to pass.
An ellipsis (...) in the command syntax indicates that your command input can include multiple values for the arguments.
Use the route-map global configuration command, and the match and set route-map configuration commands to define the conditions for redistributing routes from one routing protocol into another. Each route-map command has a list of match and set commands associated with it. The match commands specify the match criteria—the conditions under which redistribution is allowed for the current route-map command. The set commands specify the set actions—the particular redistribution actions to perform if the criteria enforced by the match commands are met. The no route-map command deletes the route map.
The match route-map configuration command has multiple formats. The match commands can be given in any order and all match commands must pass to cause the route to be redistributed according to the set actions given with the set commands. The no forms of the match commands remove the specified match criteria.
A route map can have several parts. Any route that does not match at least one match clause that relates to a route-map command is ignored; that is, the route is not advertised for outbound route maps and is not accepted for inbound route maps. If you want to modify some particular data, you must configure second route map section with an explicit match specified.
Examples
This example shows how to redistribute routes stored in the routing table with a metric of 5:
switch(config)# route-map blueberry
switch(config-route-map)# match metric 5
Related Commands
match mac-list
To redistribute routes in the routing table that match a MAC address in the MAC list, use the match mac-list command. To remove the tag entry, use the no form of this command.
match mac-list listname
no match mac-list listname
Syntax Description
listname |
MAC list name. The name can be any case-sensitive, alphanumeric string up to 32 characters. |
Command Default
No match values are defined.
Command Modes
Route-map configuration mode
Command History
|
|
|
|---|---|
6.0(2)N1(1) |
This command was introduced. |
Usage Guidelines
Use the route-map global configuration command, and the match and set route-map configuration commands to define the conditions for redistributing routes from one routing protocol into another. Each route-map command has a list of match and set commands associated with it. The match commands specify the match criteria—the conditions under which redistribution is allowed for the current route-map command. The set commands specify the set actions—the particular redistribution actions to perform if the criteria enforced by the match commands are met. The no route-map command deletes the route map.
The match route-map configuration command has multiple formats. The match commands can be given in any order and all match commands must pass to cause the route to be redistributed according to the set actions given with the set commands. The no forms of the match commands remove the specified match criteria.
A route map can have several parts. Any route that does not match at least one match clause that relates to a route-map command is ignored; that is, the route is not advertised for outbound route maps and is not accepted for inbound route maps. If you want to modify some particular data, you must configure a second route map section with an explicit match specified.
Examples
This example shows how to redistribute routes stored in the routing table that match entries in the Red MAC list:
switch# configure terminal
switch(config)# route-map blueberry
switch(config-route-map)# match mac-list Red
switch(config-route-map)#
Related Commands
match route-type
To redistribute routes of the specified type, use the match route-type command. To remove the route type entry, use the no form of this command.
match route-type {external | internal | local | nssa-external | type-1 | type-2}
no match route-type {external | internal | local | nssa-external | type-1 | type-2}
Syntax Description
Command Default
Disabled
Command Modes
Route-map configuration mode
Command History
|
|
|
|---|---|
6.0(2)N1(1) |
This command was introduced. |
Usage Guidelines
Use the route-map global configuration command, and the match and set route-map configuration commands to define the conditions for redistributing routes from one routing protocol into another. Each route-map command has a list of match and set commands associated with it. The match commands specify the match criteria—the conditions under which redistribution is allowed for the current route-map command. The set commands specify the set actions—the particular redistribution actions to perform if the criteria enforced by the match commands are met. The no route-map command deletes the route map.
The match route-map configuration command has multiple formats. The match commands can be given in any order and all match commands must pass to cause the route to be redistributed according to the set actions given with the set commands. The no forms of the match commands remove the specified match criteria.
A route map can have several parts. Any route that does not match at least one match clause that relates to a route-map command is ignored; that is, the route is not advertised for outbound route maps and is not accepted for inbound route maps. If you want to modify some particular data, you must configure a second route map section with an explicit match specified.
You can specify more than one keyword.
Examples
This example shows how to redistribute internal routes:
switch(config)# route-map blueberry
switch(config-route-map)# match route-type internal
This example shows how to redistribute internal routes and type-1 OSPF routes:
switch(config)# route-map blueberry
switch(config-route-map)# match route-type internal type-1
Related Commands
match tag
To redistribute routes in the routing table that match the specified tags, use the match tag command. To remove the tag entry, use the no form of this command.
match tag tag-value [...tag-value]
no match tag tag-value [...tag-value]
Syntax Description
tag-value |
List of one or more route tag values. Each can be an integer from 0 to 4,294,967,295. You can configure up to 32 tags. |
Command Default
No match tag values are defined.
Command Modes
Route-map configuration mode
Command History
|
|
|
|---|---|
6.0(2)N1(1) |
This command was introduced. |
Usage Guidelines
An ellipsis (...) in the command syntax indicates that your command input can include multiple values for the tag-value argument.
Use the route-map global configuration command, and the match and set route-map configuration commands to define the conditions for redistributing routes from one routing protocol into another. Each route-map command has a list of match and set commands associated with it. The match commands specify the match criteria—the conditions under which redistribution is allowed for the current route-map command. The set commands specify the set actions—the particular redistribution actions to perform if the criteria enforced by the match commands are met. The no route-map command deletes the route map.
The match route-map configuration command has multiple formats. The match commands can be given in any order and all match commands must pass to cause the route to be redistributed according to the set actions given with the set commands. The no forms of the match commands remove the specified match criteria.
A route map can have several parts. Any route that does not match at least one match clause that relates to a route-map command is ignored; that is, the route is not advertised for outbound route maps and is not accepted for inbound route maps. If you want to modify some particular data, you must configure a second route map section with an explicit match specified.
Examples
This example shows how to redistribute routes stored in the routing table with tag 5:
switch(config)# route-map blueberry
switch(config-route-map)# match tag 5
Related Commands
match vlan
To filter routes with the specified VLAN, use the match vlan command. To remove the entry for the redistributed route from the routing table, use the no form of this command.
match vlan vlan-range
no match vlan vlan-range
Syntax Description
vlan-range |
Range of VLAN that this command matches against. The range is from 1 to 4094. |
Command Default
No match VLAN values are defined.
Command Modes
Route-map configuration mode
Command History
|
|
|
|---|---|
6.0(2)N1(1) |
This command was introduced. |
Usage Guidelines
To filter routes with the specified VLAN, use the match vlan command You can specify one or more VLANs (or) range of VLANs. At least one of the specified VLANs must match for the command to pass. The command matches any VLAN that falls inclusive in the range.
Use the route-map global configuration command, and the match and set route-map configuration commands to define the conditions for redistributing routes from one routing protocol into another. Each route-map command has a list of match and set commands associated with it. The match commands specify the match criteria—the conditions under which redistribution is allowed for the current route-map command. The set commands specify the set actions—the particular redistribution actions to perform if the criteria enforced by the match commands are met. The no route-map command deletes the route map.
The match route-map configuration command has multiple formats. The match commands can be given in any order and all match commands must pass to cause the route to be redistributed according to the set actions given with the set commands. The no forms of the match commands remove the specified match criteria.
A route map can have several parts. Any route that does not match at least one match clause that relates to a route-map command is ignored; that is, the route is not advertised for outbound route maps and is not accepted for inbound route maps. If you want to modify some particular data, you must configure a second route map section with an explicit match specified
Examples
This example shows how to redistribute routes that match VLANs 5 to 10:
switch(config)# route-map blueberry
switch(config-route-map)# match vlan 5-10
Related Commands
maxas-limit
To configure the external Border Gateway Protocol (eBGP) to discard routes that have a high number of autonomous system (AS) numbers in the AS-path attribute, use the maxas-limit command. To revert to the default, use the no form of this command.
maxas-limit [number]
no maxas-limit
Syntax Description
number |
(Optional) Maximum number of AS numbers allowed in the AS-path attribute. The range is from 1 to 2000. |
Command Default
No limit
Command Modes
Router configuration mode
VRF configuration mode
Command History
|
|
|
|---|---|
6.0(2)N1(1) |
This command was introduced. |
Usage Guidelines
This command requires the LAN Enterprise Services license.
Examples
This example shows how to set the maximum number of AS numbers to 50:
switch(config)# router bgp 64496
switch(config-router)# maxas-limit 50
switch(config-router)#
Related Commands
|
|
|
|---|---|
feature bgp |
Enables the BGP feature. |
router bgp |
Creates a BGP instance. |
maximum-paths (BGP)
To control the maximum number of parallel routes that the Border Gateway Protocol (BGP) can support, use the maximum-paths command. To restore the default number of parallel routes, use the no form of this command.
maximum-paths [ibgp] number-paths
no maximum-paths [ibgp] number-paths
Syntax Description
ibgp |
(Optional) Configures the maximum interior BGP (iBGP) paths. |
number-paths |
Maximum number of parallel routes that an IP routing protocol installs in a routing table. The range is from 1 to 16. |
Command Default
8 paths
Command Modes
Router address-family configuration mode
Command History
|
|
|
|---|---|
6.0(2)N1(1) |
This command was introduced. |
Examples
This example shows how to allow a maximum of 16 paths to a destination for a BGP routing process:
switch# configure terminal
switch(config)# router bgp 64496
switch(config-router)# maximum-paths 16
switch(config-router)#
Related Commands
|
|
|
|---|---|
feature bgp |
Enables the BGP feature on the router. |
router bgp |
Enables BGP. |
maximum-prefix
To control how many prefixes can be received from a neighbor, use the maximum-prefix command. To disable this function, use the no form of this command.
maximum-prefix maximum [threshold] [restart restart-interval] [warning-only]
no maximum-prefix
Syntax Description
Command Default
This command is disabled by default. Peering sessions are disabled when the maximum number of prefixes is exceeded. If you do not configure the restart interval, a disabled session stays down after the maximum-prefix limit is exceeded.
Command Modes
Peer template configuration mode
BGP router configuration mode
BGP neighbor address-family configuration mode
Command History
|
|
|
|---|---|
6.0(2)N1(1) |
This command was introduced. |
Usage Guidelines
The number of prefixes that can be configured is limited only by the available system resources on a router.
The maximum-prefix command allows you to configure a maximum number of prefixes that a Border Gateway Protocol (BGP) routing process accepts from the specified peer. This feature provides a mechanism (in addition to distribute lists, filter lists, and route maps) to control prefixes received from a peer.
When the number of received prefixes exceeds the maximum number configured, BGP disables the peering session (by default). If you configure the restart interval, BGP automatically reestablishes the peering session at the configured time interval. If you do not configure the restart interval and a peering session is terminated because the maximum prefix limit has been exceed, the peering session is not reestablished until you enter the clear ip bgp command. If the warning-only keyword is configured, BGP sends only a log message and continues to peer with the sender.
There is no default limit on the number of prefixes that can be configured with this command. Limitations on the number of prefixes that can be configured are determined by the amount of available system resources.
Examples
This example shows how to set the maximum prefixes that are accepted from the 192.168.1.1 neighbor to 1000:
switch(config)# router bgp 64496
switch(config-router)# network 192.168.0.0
switch(config-router)# maximum-prefix 1000
switch(config-router)#
This example shows how to set the maximum number of prefixes that are accepted from the 192.168.2.2 neighbor to 5000. The router is also configured to display warning messages when 50 percent of the maximum-prefix limit (2500 prefixes) has been reached.
switch(config)# router bgp 64496
switch(config-router)# network 192.168.0.0
switch(config-router)# maximum-prefix 5000 50
switch(config-router)#
This example shows how to set the maximum number of prefixes that are accepted from the 192.168.3.3 neighbor to 2000. The router is also configured to reestablish a disabled peering session after 30 minutes.
switch(config)# router bgp 64496
switch(config-router)# network 192.168.0.0
switch(config-router)# maximum-prefix 2000 restart 30
switch(config-router)#
This example shows how to set the warning messages that are displayed when the maximum-prefix limit (500) for the 192.168.4.4 neighbor is exceeded:
switch(config)# router bgp 64496
switch(config-router)# network 192.168.0.0
switch(config-router)# maximum-prefix 500 warning-only
switch(config-router)#
This example shows how to set the maximum number of prefixes that are accepted from the 192.168.1.3 neighbor to 1500.
switch(config)# router bgp 64496
switch(config-router)# neighbor 192.168.1.3 remote-as 64497
switch(config-router-neighbor)# address-family ipv4 multicast
switch(config-router-neighbor-af)# maximum-prefix 1500
switch(config-router-neighbor-af)#
Related Commands
Feedback