如图所示，在IPv6拓扑网络中有4台路由器，现要求在这4台路由器上实现网络互联，并且因为RouterA和RouterB性能相对较低，所以还要使这两台路由器处理相对较少的数据信息。
本示例没有什么特殊要求，仅要求通过配置IS-IS基本功能实现各网络的三层互通。但要特别注意的是，示例中要求RouterA和RouterB仅需处理较少的数据，就需要把它配置成普通区域中的L1路由器。当然首先还得配置各路由器接口的IPv6地址，使它们之间三层可达。
根据以上分析可得出本示例如下的基本配置思路
① 按图中表示配置各路由器接口哦IPv6地址。
② 按图中表示配置各路由器的IS-IS IPv6基本功。
1) 配置各路由器接口的IPv6地址
【Router-A配置】
ipv6
#
interface GigabitEthernet1/0/0
ipv6 enable
ipv6 address 10:1::2/64
#
【Router-B配置】
ipv6
#
interface GigabitEthernet1/0/0
ipv6 enable
ipv6 address 10:2::2/64
#
【Router-C配置】
ipv6
#
interface GigabitEthernet1/0/0
ipv6 enable
ipv6 address 10:1::1/64
#
interface GigabitEthernet2/0/0
ipv6 enable
ipv6 address 10:2::1/64
#
interface GigabitEthernet3/0/0
ipv6 enable
ipv6 address 30::1/64
#
【Router-D配置】
ipv6
#
interface GigabitEthernet1/0/0
ipv6 enable
ipv6 address 30::2/64
#
interface GigabitEthernet2/0/0
ipv6 enable
ipv6 address 20::1/64
#
2) 配置IS-ISIPv6基本功能
假设Router-A~Router-D的系统ID分别为0000.0000.0001~0000.0000.00004，均使能缺省的1号IS-IS IPv6进程。其中RouterA和RouterB为L1路由器，RouterC为L1/2路由器，RouterD为L2路由器。
【Router-A配置】
isis 1
is-level level-1
network-entity 10.0000.0000.0001.00
#
ipv6 enable topology standard
#
interface GigabitEthernet1/0/0
ipv6 enable
ipv6 address 10:1::2/64
isis ipv6 enable 1
#
【Router-B配置】
#
isis 1
is-level level-1
network-entity 10.0000.0000.0002.00
#
ipv6 enable topology standard
#
interface GigabitEthernet1/0/0
ipv6 enable
ipv6 address 10:2::2/64
isis ipv6 enable 1
#
【Router-C配置】
isis 1
network-entity 10.0000.0000.0003.00
#
ipv6 enable topology standard
#
interface GigabitEthernet1/0/0
ipv6 enable
ipv6 address 10:1::1/64
isis ipv6 enable 1
isis circuit-level level-1
#
interface GigabitEthernet2/0/0
ipv6 enable
ipv6 address 10:2::1/64
isis ipv6 enable 1
isis circuit-level level-1
#
interface GigabitEthernet3/0/0
ipv6 enable
ipv6 address 30::1/64
isis ipv6 enable 1
isis circuit-level level-2
#
【Router-D配置】
isis 1
is-level level-2
network-entity 20.0000.0000.0004.00
#
ipv6 enable topology standard
#
#
interface GigabitEthernet1/0/0
ipv6 enable
ipv6 address 30::2/64
isis ipv6 enable 1
#
interface GigabitEthernet2/0/0
ipv6 enable
ipv6 address 20::1/64
isis ipv6 enable 1
#
#
3) 实验结果验证
【在Router-A上执行display isis Router】查看其IS-IS路由表，发现除了本区域内的两个网段路由外，还新增了一条用于访问外部区域、外部AS路由的缺省路由，这时由本区域L1/2路由器(本示例中的RouterC)下发的。
<Rotuer-A>display isis route
Route information for ISIS(1)
-----------------------------
ISIS(1) Level-1 Forwarding Table
--------------------------------
IPV4 Destination IntCost ExtCost ExitInterface NextHop Flags
--------------------------------------------------------------------------
0.0.0.0/0 10 NULL
IPV6 Dest. ExitInterface NextHop Cost Flags
--------------------------------------------------------------------------
::/0 GE1/0/0 FE80::2E0:FCFF:FEDE:38AF 10 A/-/-
10:1::/64 GE1/0/0 Direct 10 D/L/-
10:2::/64 GE1/0/0 FE80::2E0:FCFF:FEDE:38AF 20 A/-/-
Flags: D-Direct, A-Added to URT, L-Advertised in LSPs, S-IGP Shortcut,
U-Up/Down Bit Set
【在Router-C上执行命令查看IS-IS邻居的详细信息】发现其已与其他3台路由器分别建立了邻居关系。
<Router-C>display isis peer verbose
Peer information for ISIS(1)
System Id Interface Circuit Id State HoldTime Type PRI
--------------------------------------------------------------------------
0000.0000.0001 GE1/0/0 0000.0000.0003.01 Up 24s L1 64
MT IDs supported : 0(UP)
Local MT IDs : 0
Area Address(es) : 10
Peer IPv6 Address(es): FE80::2E0:FCFF:FEB4:781E
Uptime : 01:37:21
Adj Protocol : IPV6
Restart Capable : YES
Suppressed Adj : NO
Peer System Id : 0000.0000.0001
0000.0000.0002 GE2/0/0 0000.0000.0003.02 Up 24s L1 64
MT IDs supported : 0(UP)
Local MT IDs : 0
Area Address(es) : 10
Peer IPv6 Address(es): FE80::2E0:FCFF:FE95:13E5
Uptime : 01:36:57
Adj Protocol : IPV6
Restart Capable : YES
Suppressed Adj : NO
Peer System Id : 0000.0000.0002
0000.0000.0004 GE3/0/0 0000.0000.0003.03 Up 28s L2 64
MT IDs supported : 0(UP)
Local MT IDs : 0
Area Address(es) : 20
Peer IPv6 Address(es): FE80::2E0:FCFF:FE9F:14FA
Uptime : 00:06:22
Adj Protocol : IPV6
Restart Capable : YES
Suppressed Adj : NO
Peer System Id : 0000.0000.0004
Total Peer(s): 3
<Router-C>
【在Router-C上执行display isis lsdb verbose命令】查看其IS-IS LSDB的详细信息，发现有L1和L2两个LSDB。
<Router-C>display isis lsdb verbose
Database information for ISIS(1)
--------------------------------
Level-1 Link State Database
LSPID Seq Num Checksum Holdtime Length ATT/P/OL
---------------------------------------------------------------------------
0000.0000.0001.00-00 0x0000000d 0xecf6 773 86 0/0/0
SOURCE 0000.0000.0001.00
NLPID IPV6
AREA ADDR 10
INTF ADDR V6 10:1::2
Topology Standard
NBR ID 0000.0000.0003.01 COST: 10
IPV6 10:1::/64 COST: 10
0000.0000.0002.00-00 0x0000000c 0x5987 824 86 0/0/0
SOURCE 0000.0000.0002.00
NLPID IPV6
AREA ADDR 10
INTF ADDR V6 10:2::2
Topology Standard
NBR ID 0000.0000.0003.02 COST: 10
IPV6 10:2::/64 COST: 10
0000.0000.0003.00-00* 0x00000015 0x4620 1134 143 1/0/0
SOURCE 0000.0000.0003.00
NLPID IPV6
AREA ADDR 10
INTF ADDR V6 10:1::1
INTF ADDR V6 10:2::1
INTF ADDR V6 30::1
Topology Standard
NBR ID 0000.0000.0003.01 COST: 10
NBR ID 0000.0000.0003.02 COST: 10
IPV6 10:1::/64 COST: 10
IPV6 10:2::/64 COST: 10
0000.0000.0003.01-00* 0x00000009 0xa41a 1134 55 0/0/0
SOURCE 0000.0000.0003.01
NLPID IPV6
NBR ID 0000.0000.0003.00 COST: 0
NBR ID 0000.0000.0001.00 COST: 0
0000.0000.0003.02-00* 0x00000008 0xbb02 1134 55 0/0/0
SOURCE 0000.0000.0003.02
NLPID IPV6
NBR ID 0000.0000.0003.00 COST: 0
NBR ID 0000.0000.0002.00 COST: 0
Total LSP(s): 5
*(In TLV)-Leaking Route, *(By LSPID)-Self LSP, +-Self LSP(Extended),
ATT-Attached, P-Partition, OL-Overload
Level-2 Link State Database
LSPID Seq Num Checksum Holdtime Length ATT/P/OL
---------------------------------------------------------------------------
0000.0000.0003.00-00* 0x00000015 0x7e01 1134 146 0/0/0
SOURCE 0000.0000.0003.00
NLPID IPV6
AREA ADDR 10
INTF ADDR V6 10:1::1
INTF ADDR V6 10:2::1
INTF ADDR V6 30::1
Topology Standard
NBR ID 0000.0000.0003.03 COST: 10
IPV6 10:1::/64 COST: 10
IPV6 10:2::/64 COST: 10
IPV6 30::/64 COST: 10
0000.0000.0003.03-00* 0x00000002 0xf8c7 1133 55 0/0/0
SOURCE 0000.0000.0003.03
NLPID IPV6
NBR ID 0000.0000.0003.00 COST: 0
NBR ID 0000.0000.0004.00 COST: 0
0000.0000.0004.00-00 0x0000000b 0xc620 887 116 0/0/0
SOURCE 0000.0000.0004.00
NLPID IPV6
AREA ADDR 20
INTF ADDR V6 30::2
INTF ADDR V6 20::1
Topology Standard
NBR ID 0000.0000.0003.03 COST: 10
IPV6 30::/64 COST: 10
IPV6 20::/64 COST: 10
Total LSP(s): 3
*(In TLV)-Leaking Route, *(By LSPID)-Self LSP, +-Self LSP(Extended),
ATT-Attached, P-Partition, OL-Overload
<Router-C>
