Bgp Scaling; Bgp Considerations - Avaya 8800 Planning And Engineering, Network Design

BGPv4 supports classless inter-domain routing. BGPv4 advertises the IP prefix and eliminates the
concept of network class within BGP. BGP4 can aggregate routes and AS paths. BGP aggregation
does not occur when routes have different multiexit discs or next-hops.
To use BGP, you must have Ethernet Routing Switch 8800/8600 software version 3.3 or later
installed. BGP is supported on all interface modules. For large BGP environments, Avaya
recommends that you use the 8692 SF/CPU.
BGP Equal-Cost Multipath (ECMP) allows a BGP speaker to perform route balancing within an AS
by using multiple equal-cost routes submitted to the routing table by OSPF or RIP. Load balancing is
performed on a per-packet basis.
To control route propagation and filtering, RFCs 1772 and 2270 recommends that multihomed,
nontransit Autonomous Systems not run BGPv4. To address the load sharing and reliability
requirements of a multihomed user, use BGP between them.
For more information about BGP and a list of CLI BGP commands, see Avaya Ethernet Routing
Switch 8800/8600 Configuration — BGP Services, NN46205-510.
BGP navigation
•

BGP scaling

on page 125
•

BGP considerations

• BGP and other vendor interoperability
• BGP design examples
• IPv6 BGP+ on page 130
BGP scaling
For information about BGP scaling numbers, see
and Avaya Ethernet Routing Switch 8800/8600 Release Notes, NN46205-402. The Release Notes
take precedence over this document.
BGP considerations
Be aware of the following BGP design considerations.
Use the max-prefix parameter to limit the number of routes imported from a peer. This parameter
prevents nonM mode configurations from accepting more routes than they can handle. Use a setting
of 0 to accept an unlimited number of prefixes.
BGP does not operate with an IP router in nonforwarding (host-only) mode. Thus, ensure that the
routers which you want BGP to operate with are in forwarding mode.
If you are using BGP for a multi-homed AS (one that contains more than a single exit point), Avaya
recommends that you use OSPF for your IGP, and BGP for your sole exterior gateway protocol.
Otherwise, use intra-AS IBGP routing.
June 2016
on page 125
on page 126
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Planning and Engineering — Network Design
Comments on this document? infodev@avaya.com
Table 5: Supported scaling capabilities
Border Gateway Protocol
on page 29
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