HP 3100-8 v2 SI, JG221A, 3100-16 v2 SI, JG222A, 3100-24 v2 SI Configuration Manual

HP 3100 v2 Switch Series

Layer 3—IP Routing
Configuration Guide

HP 3100-8 v2 SI Switch (JG221A)

HP 3100-16 v2 SI Switch (JG222A)

HP 3100-24 v2 SI Switch (JG223A)

HP 3100-8 v2 EI Switch (JD318B)

HP 3100-16 v2 EI Switch (JD319B)

HP 3100-24 v2 EI Switch (JD320B)

HP 3100-8-PoE v2 EI Switch (JD311B)

HP 3100-16-PoE v2 EI Switch (JD312B)

HP 3100-24-PoE v2 EI Switch (JD313B)

Part number: 5998-5993

Software version: Release 5203P05

Document version: 6W100-20140603

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© Copyright 2014 Hewlett-Packard Development Company, L.P.

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i

Contents

IP routing basics ··························································································································································· 1

Overview ············································································································································································ 1
Routing table ······································································································································································ 1
Routing preference ···························································································································································· 2
Route backup ····································································································································································· 2
Displaying and maintaining a routing table ·················································································································· 2

Configuring static routing ············································································································································ 4

Introduction ········································································································································································ 4

Static route ································································································································································ 4
Default route ······························································································································································ 4

Static route configuration items ······························································································································· 4
Configuring a static route ················································································································································· 5
Displaying and maintaining static routes ······················································································································· 5

Configuring IPv6 static routing ···································································································································· 7

Overview ············································································································································································ 7
IPv6 static routes features ················································································································································· 7
Default IPv6 route ······························································································································································ 7
Configuring an IPv6 static route ······································································································································ 7
Displaying and maintaining IPv6 static routes ··············································································································· 8

Support and other resources ······································································································································· 9

Contacting HP ··································································································································································· 9

Subscription service ················································································································································· 9
Related information ··························································································································································· 9

Documents ································································································································································· 9

Websites ···································································································································································· 9
Conventions ···································································································································································· 10

Index ··········································································································································································· 12

1

IP routing basics

Overview

IP routing directs the forwarding of IP packets on routers based on a routing table. This book focuses on
unicast routing protocols.

The term "router" in this chapter refers to both routers and Layer 3 switches.

The types of interfaces that appear in any figures other than the network diagrams for configuration
examples are for illustration only. Some of them might be unavailable on your switch.

Routing table

A router maintains at least two routing tables: one global routing table and one forwarding information
base (FIB). The FIB table contains only the optimal routes, and the global routing table contains all routes.
The router uses the FIB table to forward packets. For more information about the FIB table, see Layer 3—IP
Services Configuration Guide.

Routes can be classified by different criteria, as shown in Table 1.

Table 1 Categories of routes

Criterion Categories

Destination

• Network route—Destination is a network. The subnet mask is less than 32 bits.

• Host route—Destination is a host. The subnet mask is 32 bits.

Whether the
destination is directly
connected

• Direct route—Destination is directly connected.

• Indirect route—Destination is indirectly connected.

Origin

• Direct route—A direct route is discovered by the data link protocol on an interface,

and is also called an "interface route."

• Static route—A static route is manually configured by an administrator.

• Dynamic route—A dynamic route is dynamically discovered by a routing protocol.

Static routes are easy to configure and require less system resources. They work well in small and stable
networks. In networks where topology changes may occur frequently, using a dynamic routing protocol
is better.

To display brief information about a routing table, use the display ip routing-table command:

<Sysname> display ip routing-table
Routing Tables: Public
Destinations : 7 Routes : 7

Destination/Mask Proto Pre Cost NextHop Interface

1.1.1.0/24 Direct 0 0 1.1.1.1 Vlan11
…

2

A route entry includes the following key items:

• Destination—IP address of the destination host or network.

• Mask—Mask length of the IP address.

• Pre—Preference of the route. Among routes to the same destination, the one with the highest

preference is optimal.

• Cost—If multiple routes to a destination have the same preference, the one with the smallest cost is

the optimal route.

• NextHop—Next hop.

• Interface—Output interface.

Routing preference

Different routing protocols can find different routes to the same destination. However, not all of those
routes are optimal. For route selection, direct routes and static routes are assigned different preferences.
The route with the highest preference is preferred.

The preference of a direct route is always 0 and cannot be changed. You can manually configure
preferences for any other route type. Each static route can be configured with a different preference. The
following table lists the types of routes and the default preferences. The smaller the preference value, the
higher the preference.

Table 2 Route types and their default route preferences

Routing approach Preference

Direct route

0

Static route 60

Route backup

Route backup can improve network availability. Among multiple routes to the same destination, the route
with the highest preference is the main route and all others are backup routes.

The router forwards matching packets through the main route. When the main route fails, the route with
the highest preference among the backup routes is selected to forward packets. When the main route
recovers, the router uses it to forward packets.

Displaying and maintaining a routing table

Task Command Remarks

Display information about the
routing table.

display ip routing-table [ verbose ] [ |
{ begin | exclude | include }
regular-expression ]

Available in any view