PS:我在学习ISIS的时候有几条命令让我十分困惑，通过下面的解释就很清楚了，希望对初学ISIS的朋友有帮助：
show isis topology

Displays a list of all connected routers in all areas.

Syntax: show isis topology

Description: Displays list of all connected Level-2 (inter-area) routers in all areas.

Factory Default: None.

Command Mode: Executive and privileged.

Example: The following is sample output of the show isis topology command:

router#show isis topology

IS-IS paths to level-2 routers

System Id       Metric  Next-Hop        Interface SNPA

0102.5400.5001 10 0102.5400.5001 PO0/0/0

0102.5400.5003 20 0102.5400.5001 PO0/0/0

0102.5400.5004 --

The following table describes the fields in the display:

Table 3-11. Fields Displayed by show isis topology 

Field

Description

System ID
The system identifier of the neighboring system.

Metric
A relative cost for sending information over this interface.

Next-Hop
The system identifier of the next hop from the neighboring system.

Interface
The interface over which the adjacency was established.

SNPA
The neighbor's MAC address on a broadcast network.

 

 

show isis database

Displays information the IS-IS routing database.

Syntax: show isis database [detail] [l1 | level-1 | l2 | level-2] [LSPID | hostname | hostname.nn-nn]

detail
Display detailed routing information.

l1 or level-1
Display routing information for Level-1 LSPs only.

l2 or level-2
Display routing information for Level-2 LSPs only.

LSPID
Display routing information for the specified LSP. Enter LSPID in dotted decimal format: nnnn.nnnn.nnnn.nn-nn

hostname
Displays routing information for all LSPs.

hostname.nn-nn
When hostname dynamic is enabled, display routing information for the specified LSP. Enter the LSP ID as <hostname>.nn-nn

Description: Use the show isis database command with no arguments to display summarized information about both Level-1 and Level-2 LSPs.

Use the show isis database l1 or show isis database level-1 command to display summarized information about Level-1 LSPs.

Use the show isis database l2 or show isis database level-2 command to display summarized information about Level-2 LSPs.

Use the show isis database nnnn.nnnn.nnnn.nn-nn command to display detailed information about the specified LSP.

Use the show isis database hostname.nn-nn command to display detailed information about the specified LSP when hostname dynamic is enabled.

Use the detail keyword to display the detailed information about the specified LSP(s).

Factory Default: None.

Command Mode: Executive and privileged.

Example 1: The following example shows output of the show isis database level-1 command; first with hostname dynamic disabled, second with it enabled:

router#show isis database level-1



ISIS Level-1 Link State Database

LSPID LSP Seq Num LSP Checksum LSP Holdtime ATT/P/OL

1000.5000.0001.00-00 0x0000000e 0xb8be 1200 0/0/0

1000.5000.0002.00-00 0x0000052f 0xd8e7 1199 0/0/0

1000.5000.0003.00-00 0x0000001e 0x8c80 507 0/0/0

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router#show isis database level-1



ISIS Level-1 Link State Database

LSPID LSP Seq Num LSP Checksum LSP Holdtime ATT/P/OL

NPIshelf1.00-00 0x0000000d 0xbabd 570 0/0/0

NPIshelf2.00-00 0x00000524 0x1491 1199 0/0/0

NPIshelf3.00-00 0x0000001e 0x8c80 567 0/0/0

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The following table describes the fields in the display:

Table 3-2. Fields Displayed by show isis database  

Field

Description

(Password)
The password or authentication digest, if any exists.

LSPID
The identifier for the link-state packet (LSP).

LSP Seq Num
The sequence number for the LSP. Every time a LSP is updated, the sequence number is incremented so that a router can determine if the LSP it has just received is indeed newer than one it already has in its database.

LSP Checksum
The checksum of the LSP. If the ignore-lsp-error command has been entered, LSPs with incorrect checksums are discarded.

LSP Holdtime
The remaining time, in seconds, that this LSP is valid.

ATT/P/OL
ATT - A 1 indicates the router that originated this LSP is attached through a Level 2 router to at least one other area.

P- A 1 indicates the router that originated this LSP has partition repair capability.

OL- A 1 indicates the router that originated this LSP is overloaded. This LSP should not be used.

Example 2: The following is sample output of the show isis database detail command:

router#show isis database detail



ISIS Level-1 Link State Database

LSPID LSP Seq Num LSP Checksum LSP Holdtime ATT/P/OL

NPIshelf1.00-00 0x0000000e 0xb8be 940 0/0/0

Area Address: 47

NLPID: 0xCC

Router ID: 10.50.0.1

Hostname: NPIshelf1

Metric: 10 IS 1000.5000.0002.00, Extended

Administrative color: 0x00000000

IPV4 interface address: 10.50.1.1

IPV4 neighbor address: 10.50.1.2

Max link bandwidth: 225375008.000 Bytes/sec.

Max reservable bandwidth: 225375008.000 Bytes/sec.

Priority 0 Available reservation: 225375008.000 Bytes/sec.

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.

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    Priority 7 Available reservation: 225375008.000 Bytes/sec.

TE default metric: 1

Metric: 10 IS 1000.5000.0003.00, Extended

Administrative color: 0x00000000

IPV4 interface address: 10.50.4.1

IPV4 neighbor address: 10.50.4.2

Max link bandwidth: 300624992.000 Bytes/sec.

Max reservable bandwidth: 300624992.000 Bytes/sec.

Priority 0 Available reservation: 300624992.000 Bytes/sec.

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.

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    Priority 7 Available reservation: 300624992.000 Bytes/sec.

TE default metric: 1

IP Address: 10.50.0.1

IP Address: 10.50.1.1

IP Address: 10.50.4.1

Metric: 10 IP 10.50.0.1/32, Extended, Up/Down bit: 0,

Metric: 10 IP 10.50.1/24, Extended, Up/Down bit: 0,

Metric: 10 IP 10.50.4/24, Extended, Up/Down bit: 0,

  Metric: 10 IP 191.191.191.191/32, Extended, Up/Down bit: 0

Metric: 10 IP 191.194.1/24, Extended, Up/Down bit: 0

Metric: 10 IP 55.55.55/24, Extended, Up/Down bit: 0

Metric: 10 IP 194.10.1/24, Extended, Up/Down bit: 0

ha193.00-00 0x00000096 0xa9b4 1070 0/0/0

Area Address: 25.0001

NLPID: 0xCC

Hostname: ha193

ha193.00-01 0x00000096 0x30dd 1070 0/0/0

Metric: 10 IS 0001.0001.0193.01, Extended

ha193.00-02 0x00000096 0xdc9c 1070 0/0/0

IP Address: 55.55.55.3

IP Address: 194.10.2.2

Metric: 10 IP 55.55.55/24, Extended, Up/Down bit: 0

Metric: 10 IP 194.10.2/24, Extended, Up/Down bit: 0

ha193.01-00 0x00000079 0x1819 1070 0/0/0

NLPID: 0xCC

Metric: 0 IS 0001.0001.0193.00, Extended

Metric: 0 IS 0001.0001.0191.00, Extended


Example 3: The following is sample output of the show isis database detail command when L2 into L1 leaked routes are present:

router#show isis database detail



ISIS Level-1 Link State Database

LSPID LSP Seq Num LSP Checksum LSP Holdtime ATT/P/OL

ha191.00-00 0x00000092 0xa1c2 1149 0/0/0

Area Address: 25.0001

NLPID: 0xCC

Hostname: ha191

ha191.00-01 0x00000092 0x4ac7 1149 0/0/0

Metric: 10 IS 0001.0001.0193.01, Extended

ha191.00-02 0x00000092 0xe3a9 1149 0/0/0

IP Address: 191.191.191.191

IP Address: 191.194.1.2

IP Address: 55.55.55.1

IP Address: 194.10.1.2

Metric: 10 IP 12.2.41.19/32, Extended, Up/Down bit: 1

Metric: 10 IP 12.2.41.20/32, Extended, Up/Down bit: 1

Metric: 10 IP 12.2.41.21/32, Extended, Up/Down bit: 1

Metric: 10 IP 12.2.41.22/32, Extended, Up/Down bit: 1

Metric: 10 IP 12.2.41.23/32, Extended, Up/Down bit: 1

Metric: 10 IP 12.2.41.24/32, Extended, Up/Down bit: 1

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The following table describes the fields in the display:

Table 3-3. Fields Displayed by show isis database  detailed  

Field

Description

Area Address
Reachable area addresses from the router. For L1 LSPs, these are the area addresses configured manually on the originating router. For L2 LSPs, these are all the area addresses for the area this route belongs to.

NLPID

network layer protocol identifier. 0xcc = IP

Router ID

 

Hostname
Specifies the configured hostname for this router.

Metric:
IS-IS metric for the cost of the adjacency between the originating router and the advertised neighbor, or the metric of the cost to get from the advertising router to the advertised destination.

Metric ES
End system neighbors Metric

Administrative color
Specifies administrative colors assigned to this link.

Max link bandwidth
Specifies the maximum usable bandwidth for the link.

Max reservable bandwidth
Specifies the maximum reserved usable bandwidth for the link

TE default metric
Traffic Engineering metric that determines the relative preference for an interface during tunnel creation.

Prefix Neighbor
Reachable Address Prefix Neighbors.

IP Address
IP interface Address. The IP address of one or more interfaces on this router.

 

 

 

show isis neighbor

Displays information about IS-IS neighbors.

Syntax: show isis neighbor

Description: Displays the information about IS-IS neighbors.

Factory Default: None.

Command Mode: Executive and privileged.

Example 1: The following is sample output from the show isis neighbor command:

router#show isis neighbor

System ID SNPA Interface State HoldTime Type Pri

1000.5000.0002 CL 12 Up 101 L1

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Example 2: The following is sample output of the show isis neighbor when hostname dynamic is enabled:

router#show isis neighbor

System ID SNPA Interface State HoldTime Type Pri

NPIshelf2 CL 12 Up 101 L1

NPIshelf3 POS 1/6/1 Up 97 L1

 

Table 3-7. Fields Displayed by show isis neighbor 

Field

Description

System ID
The system identifier of the neighboring system, in either xxxx.xxxx.xxxx or hostname format.

SNPA
The neighbor's MAC address on a broadcast network.

Interface
The interface over which the adjacency was established.

State
The state of the neighboring router.

HoldTime
How many seconds until the adjacency is deleted (unless it is reset).

Type
The type of adjacency. Types can be either L1 for Level 1 or L2 for Level 2.

Priority
The priority assigned to each router.

 

 

show clns neighbors

Description: 
Displays both ES and IS neighbors.
Syntax: 
show clns neighbors [ interfaceType interfaceSpecifier ] [ detail ] [ filter ]