Bgp Scaling; Bgp Considerations - Avaya 8800 Planning And Engineering

Layer 3 network design
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
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BGP scaling

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BGP considerations

• BGP and other vendor interoperability
• BGP design examples
• IPv6 BGP+
BGP scaling
For information about BGP scaling numbers, see
page 27 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.
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Table 5: Supported scaling capabilities on
November 2010