Design Reference
Table Of Contents
- Contents
- Chapter 1: Introduction
- Chapter 2: New in this release
- Chapter 3: Network design fundamentals
- Chapter 4: Hardware fundamentals and guidelines
- Chapter 5: Optical routing design
- Chapter 6: Platform redundancy
- Chapter 7: Link redundancy
- Chapter 8: Layer 2 loop prevention
- Chapter 9: Spanning tree
- Chapter 10: Layer 3 network design
- Chapter 11: SPBM design guidelines
- Chapter 12: IP multicast network design
- Multicast and VRF-lite
- Multicast and MultiLink Trunking considerations
- Multicast scalability design rules
- IP multicast address range restrictions
- Multicast MAC address mapping considerations
- Dynamic multicast configuration changes
- IGMPv3 backward compatibility
- IGMP Layer 2 Querier
- TTL in IP multicast packets
- Multicast MAC filtering
- Guidelines for multicast access policies
- Multicast for multimedia
- Chapter 13: System and network stability and security
- Chapter 14: QoS design guidelines
- Chapter 15: Layer 1, 2, and 3 design examples
- Chapter 16: Software scaling capabilities
- Chapter 17: Supported standards, RFCs, and MIBs
- Glossary
In an environment with a mix of non-Avaya and Avaya switches and routers, you may need to
manually modify the OSPF parameter RtrDeadInterval to 40 seconds.
Border Gateway Protocol
Use the Border Gateway Protocol (BGP) to ensure that the switch can communicate with other
BGP-speaking routers on the Internet backbone. BGP is an exterior gateway protocol that
exchanges network reachability information with other BGP systems in the same or other
autonomous systems (AS). This network reachability information includes information about
the AS list that the reachability information traverses. By using this information, you can prune
routing loops and enforce policy decisions at the AS level.
BGP performs routing between two sets of routers that operate in different autonomous
systems. An AS can use two kinds of BGP: Interior BGP (IBGP), which refers to the protocol
that BGP routers use within an autonomous system, and Exterior BGP (EBGP), which refers
to the protocol that BGP routers use across two different autonomous systems. BGP
information is redistributed to Interior Gateway Protocols (IGP) that run in the autonomous
system.
BGP version 4 (BGPv4) supports classless inter-domain routing (CIDR). 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 Multi-Exit
Discriminators (MED) or next-hops.
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. BGP
performs load balancing on an individual packet basis.
To control route propagation and filtering, RFC1772 and RFC2270 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 concepts and configuration, see Avaya Virtual Services
Platform 4000 Configuration — BGP Services, NN46251-507.
BGP implementation guidelines
To successfully implement BGP in a Virtual Services Platform 4000 network, follow these
guidelines:
• BGP does not operate with an IP router in nonforwarding (host-only) mode. Ensure that
the routers with which you want BGP to operate are in forwarding mode.
• If you use BGP for a multi-homed AS (one that contains more than a single exit point),
Avaya recommends that you use OSPF for the IGP, and BGP for the sole exterior gateway
protocol. Otherwise, use intra-AS IBGP routing.
• If OSPF is the IGP, use the default OSPF tag construction. The use of EGP or the
modification of the OSPF tags makes network administration and proper configuration of
BGP path attributes difficult.
Layer 3 network design
66 Network Design Reference for Avaya VSP 4000 February 2014
Comments? infodev@avaya.com