ARISTA - BGP Commands: Difference between revisions
Created page with "Category:Wiki == Configuring BGP on Arista EOS == To start configuring BGP, you need to enter global configuration mode and enable BGP for a specific Autonomous System (AS). <nowiki> router bgp [AS_NUMBER]</nowiki> Example: <nowiki> router bgp 65001</nowiki> == BGP Neighbors Configuration == You can define BGP neighbors, which are other BGP routers with which your device will exchange routing information. ### Add a Neighbor <nowiki> neighbor [IP_ADDRESS] r..." Tag: Recreated |
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== Configuring BGP on Arista EOS == | == Configuring BGP on Arista EOS == | ||
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You can define BGP neighbors, which are other BGP routers with which your device will exchange routing information. | You can define BGP neighbors, which are other BGP routers with which your device will exchange routing information. | ||
Add a Neighbor | |||
<nowiki> | <nowiki> | ||
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neighbor 192.168.1.1 remote-as 65002</nowiki> | neighbor 192.168.1.1 remote-as 65002</nowiki> | ||
Specify the Neighbor’s Address Family | |||
<nowiki> | <nowiki> | ||
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address-family ipv4 unicast</nowiki> | address-family ipv4 unicast</nowiki> | ||
Configure the Neighbor's Update Source | |||
<nowiki> | <nowiki> | ||
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neighbor 192.168.1.1 update-source Ethernet1</nowiki> | neighbor 192.168.1.1 update-source Ethernet1</nowiki> | ||
Configure BGP Peer Group | |||
You can also configure peer groups to simplify neighbor configurations. | You can also configure peer groups to simplify neighbor configurations. | ||
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You can configure BGP for different address families (IPv4, IPv6) using the address-family command. | You can configure BGP for different address families (IPv4, IPv6) using the address-family command. | ||
IPv4 Unicast Address Family | |||
<nowiki> | <nowiki> | ||
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address-family ipv4 unicast</nowiki> | address-family ipv4 unicast</nowiki> | ||
IPv6 Unicast Address Family | |||
<nowiki> | <nowiki> | ||
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BGP supports multiple path attributes to control route selection and advertisement. Below are some common attributes that can be configured. | BGP supports multiple path attributes to control route selection and advertisement. Below are some common attributes that can be configured. | ||
Configure Local Preference | |||
Local preference is used to prefer a particular route within an AS. | Local preference is used to prefer a particular route within an AS. | ||
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bgp bestpath local-preference 200</nowiki> | bgp bestpath local-preference 200</nowiki> | ||
Configure MED (Multi-Exit Discriminator) | |||
MED is used to influence the route selection across different ASes. | MED is used to influence the route selection across different ASes. | ||
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bgp bestpath med 50</nowiki> | bgp bestpath med 50</nowiki> | ||
Configure Weight | |||
Weight is a Cisco-specific attribute that influences route preference. It is local to the router and does not propagate to other routers. | Weight is a Cisco-specific attribute that influences route preference. It is local to the router and does not propagate to other routers. | ||
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BGP allows filtering of incoming and outgoing routes to control the routing table and BGP advertisements. | BGP allows filtering of incoming and outgoing routes to control the routing table and BGP advertisements. | ||
Prefix List | |||
You can use prefix lists to filter specific IP prefixes. | You can use prefix lists to filter specific IP prefixes. | ||
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ip prefix-list myFilter permit 192.168.0.0/16</nowiki> | ip prefix-list myFilter permit 192.168.0.0/16</nowiki> | ||
Route Map | |||
Route maps can be used for more advanced filtering and route manipulation. | Route maps can be used for more advanced filtering and route manipulation. | ||
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route-map MyRouteMap permit 10</nowiki> | route-map MyRouteMap permit 10</nowiki> | ||
Apply a Route Map to a BGP Neighbor | |||
<nowiki> | <nowiki> | ||
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neighbor 192.168.1.1 route-map MyRouteMap in</nowiki> | neighbor 192.168.1.1 route-map MyRouteMap in</nowiki> | ||
Distribute List | |||
A distribute list can be used to filter routes based on access lists. | A distribute list can be used to filter routes based on access lists. | ||
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== BGP Route Advertisement == | == BGP Route Advertisement == | ||
Advertise Networks | |||
You can advertise networks into BGP using the `network` command. | You can advertise networks into BGP using the `network` command. | ||
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network 10.0.0.0/24</nowiki> | network 10.0.0.0/24</nowiki> | ||
Advertise Aggregate Address | |||
You can advertise a summarized or aggregate address. | You can advertise a summarized or aggregate address. | ||
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BGP allows configuration of timers for various BGP operations, including keepalive and hold timers. | BGP allows configuration of timers for various BGP operations, including keepalive and hold timers. | ||
Configure Keepalive and Hold Timers | |||
<nowiki> | <nowiki> | ||
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neighbor 192.168.1.1 timers 30 90</nowiki> | neighbor 192.168.1.1 timers 30 90</nowiki> | ||
Configure BGP Maximum Prefix Limit | |||
<nowiki> | <nowiki> | ||
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Once BGP is configured, there are several show commands to verify and troubleshoot BGP. | Once BGP is configured, there are several show commands to verify and troubleshoot BGP. | ||
Show BGP Summary | |||
<nowiki> | <nowiki> | ||
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This will display the BGP neighbors, state, and prefix counts. | This will display the BGP neighbors, state, and prefix counts. | ||
Show BGP Route | |||
<nowiki> | <nowiki> | ||
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This will display the BGP routing table. | This will display the BGP routing table. | ||
Show BGP Neighbor Information | |||
<nowiki> | <nowiki> | ||
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This will display detailed information about a specific BGP neighbor. | This will display detailed information about a specific BGP neighbor. | ||
Show BGP Advertised Routes | |||
<nowiki> | <nowiki> | ||
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== Troubleshooting BGP == | == Troubleshooting BGP == | ||
BGP Debugging Commands | |||
You can enable debugging to capture BGP activity. | You can enable debugging to capture BGP activity. | ||
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This command will show live BGP updates, state changes, and route advertisements. | This command will show live BGP updates, state changes, and route advertisements. | ||
Display BGP Events | |||
<nowiki> | <nowiki> | ||
Latest revision as of 07:20, 17 January 2026
Configuring BGP on Arista EOS
To start configuring BGP, you need to enter global configuration mode and enable BGP for a specific Autonomous System (AS).
router bgp [AS_NUMBER]
Example:
router bgp 65001
BGP Neighbors Configuration
You can define BGP neighbors, which are other BGP routers with which your device will exchange routing information.
Add a Neighbor
neighbor [IP_ADDRESS] remote-as [AS_NUMBER]
Example:
neighbor 192.168.1.1 remote-as 65002
Specify the Neighbor’s Address Family
address-family [ipv4 | ipv6] unicast
Example:
address-family ipv4 unicast
Configure the Neighbor's Update Source
neighbor [IP_ADDRESS] update-source [INTERFACE_NAME]
Example:
neighbor 192.168.1.1 update-source Ethernet1
Configure BGP Peer Group
You can also configure peer groups to simplify neighbor configurations.
neighbor [PEER_GROUP_NAME] peer-group neighbor [PEER_GROUP_NAME] remote-as [AS_NUMBER]
Example:
neighbor PeerGroup1 peer-group neighbor PeerGroup1 remote-as 65002
BGP Address Family Configuration
You can configure BGP for different address families (IPv4, IPv6) using the address-family command.
IPv4 Unicast Address Family
address-family ipv4 unicast
Example:
router bgp 65001 address-family ipv4 unicast
IPv6 Unicast Address Family
address-family ipv6 unicast
Example:
router bgp 65001 address-family ipv6 unicast
BGP Path Attributes Configuration
BGP supports multiple path attributes to control route selection and advertisement. Below are some common attributes that can be configured.
Configure Local Preference
Local preference is used to prefer a particular route within an AS.
bgp bestpath local-preference [VALUE]
Example:
bgp bestpath local-preference 200
Configure MED (Multi-Exit Discriminator)
MED is used to influence the route selection across different ASes.
bgp bestpath med [VALUE]
Example:
bgp bestpath med 50
Configure Weight
Weight is a Cisco-specific attribute that influences route preference. It is local to the router and does not propagate to other routers.
neighbor [IP_ADDRESS] weight [VALUE]
Example:
neighbor 192.168.1.1 weight 100
BGP Route Filtering
BGP allows filtering of incoming and outgoing routes to control the routing table and BGP advertisements.
Prefix List
You can use prefix lists to filter specific IP prefixes.
ip prefix-list [PREFIX_LIST_NAME] permit|deny [NETWORK/MASK]
Example:
ip prefix-list myFilter permit 192.168.0.0/16
Route Map
Route maps can be used for more advanced filtering and route manipulation.
route-map [MAP_NAME] permit|deny [SEQUENCE_NUMBER]
Example:
route-map MyRouteMap permit 10
Apply a Route Map to a BGP Neighbor
neighbor [IP_ADDRESS] route-map [MAP_NAME] in|out
Example:
neighbor 192.168.1.1 route-map MyRouteMap in
Distribute List
A distribute list can be used to filter routes based on access lists.
neighbor [IP_ADDRESS] distribute-list [ACCESS_LIST_NAME] in|out
Example:
neighbor 192.168.1.1 distribute-list MyAccessList out
BGP Route Advertisement
Advertise Networks
You can advertise networks into BGP using the `network` command.
network [NETWORK/MASK]
Example:
network 10.0.0.0/24
Advertise Aggregate Address
You can advertise a summarized or aggregate address.
aggregate-address [NETWORK/MASK]
Example:
aggregate-address 10.0.0.0/16
BGP Timers and Parameters
BGP allows configuration of timers for various BGP operations, including keepalive and hold timers.
Configure Keepalive and Hold Timers
neighbor [IP_ADDRESS] timers [KEEPALIVE_INTERVAL] [HOLD_TIME]
Example:
neighbor 192.168.1.1 timers 30 90
Configure BGP Maximum Prefix Limit
neighbor [IP_ADDRESS] maximum-prefix [MAX_PREFIXES]
Example:
neighbor 192.168.1.1 maximum-prefix 5000
BGP Show Commands
Once BGP is configured, there are several show commands to verify and troubleshoot BGP.
Show BGP Summary
show ip bgp summary
This will display the BGP neighbors, state, and prefix counts.
Show BGP Route
show ip bgp
This will display the BGP routing table.
Show BGP Neighbor Information
show ip bgp neighbors [IP_ADDRESS]
This will display detailed information about a specific BGP neighbor.
Show BGP Advertised Routes
show ip bgp neighbors [IP_ADDRESS] advertised-routes
This will display the routes advertised to a specific BGP neighbor.
Troubleshooting BGP
BGP Debugging Commands
You can enable debugging to capture BGP activity.
debug ip bgp
This command will show live BGP updates, state changes, and route advertisements.
Display BGP Events
show logging | include BGP
This will filter the log for BGP-specific events and errors.
Useful Links
- [Arista EOS Documentation](https://www.arista.com/en/support/eos)
- [RFC 4271 - BGPv4 Specification](https://tools.ietf.org/html/rfc4271)
- [Arista BGP Configuration Guide](https://www.arista.com/en/support/bgp)
- [Cisco BGP Command Reference](https://www.cisco.com/c/en/us/td/docs/iosxr/ncs5500/bgp/bgp-command-reference-650/b-bgp-cg/b-bgp-cg_chapter_010.html)
