Web Management Guide

Chapter 1 | Introduction
Description of Software Features
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in each packet. Based on network policies, different kinds of traffic can be marked
for different kinds of forwarding.
IP Routing The switch provides Layer 3 IP routing. To maintain a high rate of throughput, the
switch forwards all traffic passing within the same segment, and routes only traffic
that passes between different subnetworks. The wire-speed routing provided by
this switch lets you easily link network segments or VLANs together without having
to deal with the bottlenecks or configuration hassles normally associated with
conventional routers.
Routing for unicast traffic is supported with static routing, Open Shortest Path First
(OSPF) protocol, and Border Gateway Protocol (BGP).
Static Routing – Traffic is automatically routed between any IP interfaces
configured on the switch. Routing to statically configured hosts or subnet
addresses is provided based on next-hop entries specified in the static routing
table.
OSPF – This approach uses a link state routing protocol to generate a shortest-path
tree, then builds up its routing table based on this tree. OSPF produces a more
stable network because the participating routers act on network changes
predictably and simultaneously, converging on the best route more quickly than
RIP.
BGP – This protocol uses a path vector approach to connect autonomous systems
(AS) on the Internet. BGP maintains a table of IP network prefixes which designate
network reachability among autonomous systems based the path of ASs to the
destination, and next hop information. It makes routing decisions based on path,
network policies and/or rule sets. For this reason, it is more appropriately termed a
reachability protocol rather than a routing protocol.
Policy-based Routing for BGP – The next-hop behavior for ingress IP traffic can be
determined based on matching criteria.
Equal-cost Multipath
Load Balancing
When multiple paths to the same destination and with the same path cost are
found in the routing table, the Equal-cost Multipath (ECMP) algorithm first checks if
the cost is lower than that of any other routing entries. If the cost is the lowest in
the table, the switch will use up to eight paths having the lowest path cost to
balance traffic forwarded to the destination. ECMP uses either equal-cost unicast
multipaths manually configured in the static routing table, or equal-cost multipaths
dynamically detected by the Open Shortest Path Algorithm (OSPF). In other words,
it uses either static or unicast routing entries, not both.
Router Redundancy Virtual Router Redundancy Protocol (VRRP) uses a virtual IP address to support a
primary router and multiple backup routers. The backups can be configured to take
over the workload if the master fails or to load share the traffic. The primary goal of