Layer 3 Features; Convergence Features - Avaya X330W2-DS1 User Manual

Chapter 1 Overview

Layer 3 Features

• Supports RIP v1/v2 routing protocols
• Supports Single Area OSPF routing protocol - the X330WAN can be configured
as an OSPF Autonomous System Boundary Router (ASBR) by configuration of
route redistribution. The X330WAN can be installed in the OSPF backbone area
(area 0.0.0.0) or in any OSPF area that is part of a multiple areas network. The
X330WAN cannot be configured to be an OSPF area border router itself.
• Supports VRRP redundancy protocol - supported only on the X330WAN's LAN
(Fast Ethernet and Fabric Fast Ethernet) ports.
• Supports Equal-Cost MultiPath (ECMP) - allows load balancing by splitting
traffic between several equivalent paths.
• Supports Distribution Lists - these lists define which routers are trusted
regarding OSPF. Routing information is only allowed to be transmitted to or
received from the trusted routers.

Convergence Features

• Priority queueing - the X330WAN supports the ability to separate traffic into 4
strict priority queues per interface. The assignment of placement in the queues
is performed using Policy.
• Guaranteed delay for VoIP traffic - the X330WAN supports VoIP Queue mode.
In this mode traffic labelled as voice traffic receives preference to all other
traffic. The X330WAN default mode is optimized for the G.729 codec.
• Random Early Detect (RED) - the X330WAN uses RED in order to improve the
performance of the network when overloaded. RED sends signals to
transmitting hosts stating that the bandwidth is limited, and that they should
reduce their transmission speed.
• RTP Header Compression - The Real Time Protocol (RTP) is the basis of
common VoIP traffic. RTP runs over UDP, and incurs a 12-byte header on top of
other (IP, UDP) headers. Running on PPP or Frame-Relay, this protocol can be
compressed.
X330WAN RTP Header Compression process is based on the fact that the
packet order on a PPP link is preserved. As a result, many times only the
"deltas" from the previous packet's header needs to be sent, and not the full
header. Moreover, since the "deltas" are often constant, the second order
"delta" is 0 and does not need to be transmitted. In many cases, all three
headers (IP+UDP+RTP~40 bytes) can be reduced to a size of 2-4 bytes.
• Fragmentation and Reassembly - the X330WAN supports:
— Fragmentation of IP packets according to RFC 791.
— Reassembly of IP packets destined only to the X330WAN (i.e., packets that
have its IP address as their destination address).
Fragmented IP packets with destinations other than this X330WAN will NOT be
reassembled by this X330WAN.
4 Avaya X330W-2DS1 User's Guide