Command Line Interface Reference Guide > The Configuration Menu > /cfg/l3/bgp Border Gateway Protocol Configuration
/cfg/l3/bgp
Border Gateway Protocol Configuration
The Border Gateway Protocol (BGP) enables routers on a network to share and advertise routing information with each other about the segments of the IP address space they can access within their network, and with routers on external networks. BGP allows you to decide what is the “best” route for a packet to take from your network to a destination on another network, rather than simply setting a default route from your border routers to your upstream providers. BGP is defined in RFC 1771.
Alteon can advertise its IP interfaces and virtual server IP addresses using BGP and take BGP feeds from as many as 16 BGP router peers. This allows more resilience and flexibility in balancing traffic from the Internet.
Note: BGP will not advertise or use routes unless explicitly configured to do so with an export or import policy. FRR BGP requires incoming and outgoing filters to be applied for eBGP sessions as part of RFC-8212 compliance. Without the incoming filter, no routes will be accepted. Without the outgoing filter, no routes will be announced.
The Border Gateway Protocol menu lets you configure Alteon to receive routes and to advertise static routes, fixed routes, and virtual server IP addresses with other internal and external routers.
BGP is turned off by default.
 
[Border Gateway Protocol Menu]
peer     - Peer menu
aggr     - Aggregation menu
as       - Set Autonomous System (AS) number

      asmode   - Set Autonomous System (AS) mode
      advfip   - Enable/Disable advertising floating IP address
      grcrstrt  - Graceful Restart Menu
      mode      - Set BGP mode (FRR or Legacy)
      stdclist  - Standard Community List Menu
      extclist  - Extended Community List Menu
      larclist  - Large Community List Menu
maxpath   - Set Max AS Path Length
     scanfreq  - Set Scan frequency
      ecmp      - Set ECMP mode
      vipa      - Enable/Disable sending VIP advertisement
pref    - Set Local Preference
on   - Globally turn BGP ON
off  - Globally turn BGP OFF
cur     - Display current BGP configuration
 
Note: Fixed routes are subnet routes. There is one fixed route per IP interface.
 
Border Gateway Protocol Menu (/cfg/l3/bgp) 
Command Syntax and Usage
peer <peer number (1-16)>
 
Displays the BGP Peer menu used to configure each BGP peer. Each border router, within an autonomous system (AS), exchanges routing information with routers on other external networks. To view this menu, see /cfg/l3/bgp/peer <peer number> BGP Peer Configuration Menu.
Default: enable
aggr <aggregate number (1-16)>
 
Displays the Aggregation menu. To view this menu, see /cfg/l3/bgp/aggr <aggregate number> BGP Aggregate Routing Configuration Menu.
Default: enable
as <autonomous system number (1-65535.65535)|(1-4294967295)>
 
Sets the Autonomous System Number (ASN) for this autonomous system.
An AS is the unit of a router policy, either a single network or a group of networks, that is controlled by a common network administrator on behalf of an administrative entity (such as a university, a business enterprise, or a business division). An AS is assigned a globally unique number called an ASN. An autonomous system shares routing information with other autonomous systems using the Border Gateway Protocol (BGP).
Values:
*1 – 4294967295 (when asdot is disabled)
*1 – 65535.65535 (when asdot is enabled)
Default: 0
asmode <2byte|4byte>
 
Sets the Autonomous System Number mode.
Default: 4byte
asdot <d|e)>
 
Specifies whether to enable or disable AS DOT Notation (asdot).
When disabled, the 4-byte values are represented in decimal format in the autonomous system number (as). Whereas when enabled, as is represented by a dot notation. This means that asdot represents as numbers less than 65536 using as plain notation and as numbers above 65536 using asdot.
Default: disabled
advfip
 
Specifies whether to globally enable floating IP advertisement.
Default: disabled
grcrstrt
 
Displays the BGP Graceful Restart menu. To view this menu, see /cfg/l3/bgp/grcrstrt BGP Graceful Restart Menu.
Note: This option is only available if BGP mode FRR was selected (and after reboot).
mode <F-FRR | L-Legacy>
 
Specifies the BGP mode.
Note: In Legacy mode, Alteon advertises local routing information with a fixed route distribution enabled for all IP masks except for a mask with a prefix length of 32 (255.255.255.255).
Values: F-FRR, L-Legacy
Default: Legacy
Note: Changing the BGP mode requires a platform reboot.
stdclist
 
Displays the BGP Standard Community List menu. To view this menu, see /cfg/l3/bgp/stdclist BGP Standard Community List Menu.
Note: This option is only available if BGP mode FRR was selected (and after reboot).
extclist
 
Displays the BGP Extended Community List menu. To view this menu, see /cfg/l3/bgp/extclist BGP Extended Community List Menu.
Note: This option is only available if BGP mode FRR was selected (and after reboot).
larclist
 
Displays the BGP Large Community List menu. To view this menu, see /cfg/l3/bgp/larclist BGP Large Community List Menu.
Note: This option is only available if BGP mode FRR was selected (and after reboot).
maxpath <max AS path length (1-127)>
 
Limits the maximum length of an accepted AS Path. Paths greater than this value are ignored. This is designed to protect the MP CPU, memory resources, and routing table from BGP-based attacks, BGP errors and probes designed to locate BGP speaking devices that do not limit the maximum AS Path.
Default: 50
pref <preference (0-4294967294)>
 
Sets the local preference. The path with the higher value is preferred.
When multiple peers advertise the same route, use the route with the shortest AS path as the preferred route if you are using eBGP, or use the local preference if you are using iBGP.
scanfreq
 
Sets the scan frequency.
Values: 1-120
ecmp <ibgp|ebgp|eibcp|off>
 
ECMP (Equal Cost Multipath Protocol) for BGP enables Alteon to distribute egress IPv4 traffic between multiple next hop routers that have equal cost path to the destination. You can specify ECMP to work with different peer types or disable it.
This configuration is only available when the FRR mode is on.
Values:
*off — Disables ECMP.
*ibgp — Enables ECMP to work with the ibgp peer type.
*ebgp — Enables ECMP to work with the ebgp peer type.
*eibgp — Enables ECMP to work with the ebgp and ibgp peer types.
Default: off
on
 
Globally turns BGP on.
off
 
Globally turns BGP off.
cur
 
Displays the current BGP configuration.