User manual

Publication 1783-UM003D-EN-E - December 2009 51
Chapter 2
Types of Routing
Stratix 8300 switches can route packets by using these methods:
Feature Description
Static routing Static routing forwards packets from predetermined ports through a single path into and
out of a network. Static routing is secure and uses little bandwidth, but does not
automatically respond to changes in the network. Static routing is manually configured by
the user for each path in the system.
Dynamic routing Dynamic routing protocols are used by Layer 3 switches to dynamically calculate the best
route for forwarding traffic. There are two types of dynamic routing protocols:
• Distance-vector protocols
• Link-state protocols
Layer 3 switches using distance-vector protocols maintain routing tables with distance
values of networked resources, and periodically pass these tables to their neighbors.
Distance-vector protocols use one or a series of metrics for calculating the best routes.
These protocols are easy to configure and use.
Distance-vector protocols supported by the switch are Routing Information Protocol (RIP),
which uses a single distance metric (cost) to determine the best path and Border Gateway
Protocol (BGP), which adds a path vector mechanism. The switch also supports the Open
Shortest Path First (OSPF) link-state protocol and Enhanced IGRP (EIGRP), which adds
some link-state routing features to traditional Interior Gateway Routing Protocol (IGRP) to
improve efficiency.
Routers using link-state protocols maintain a complex database of network topology,
based on the exchange of link-state advertisements (LSAs) between routers. LSAs are
triggered by an event in the network, which speeds up the convergence time or time
required to respond to these changes. Link-state protocols respond quickly to topology
changes, but require greater bandwidth and more resources than distance-vector
protocols
Unicast routing Unicast routing is used for all network processes where a private or unique resource is
requested.
Multicast routing In multicast routing, routers create optimal distribution paths for data sent to a multicast
destination address spanning tree in real-time. Multicast routing protocols supported are
PIM (SM, SM, SDM), DVMRP tunneling.
Redundant routing Redundant routing localizes the effects of route failures, and reduces control traffic
overhead and route reconfiguration time by providing a redundant network path.
Redundant routing protocols supported are HSRP (Hot Standby Router Protocol) and CEF
(Cisco Express Forwarding).
IPv6 routing IPv6 network segments, also known as links or subnets, are connected by IPv6 routers,
which are devices that pass IPv6 packets from one network segment to another. EIGRP is
the supported protocol.
VRF Lite Virtual Routing and Forwarding (VRF) allows multiple instances of a routing table to
coexist within the same router at the same time. Because the routing instances are
independent, the same or overlapping IP addresses can be used without conflicting with
each other. The simplest form of VRF implementation is VRF Lite. In this implementation,
each router within the network participates in the virtual routing environment in a
peer-based fashion.