Catalyst 5000 Family Software Configuration Guide (6.3 and 6.4)
Checking Port Status and Connectivity

Table Of Contents

Checking Port Status and Connectivity

Checking Module Status

Checking Port Status

Checking Port Capabilities

Using Telnet

Using Secure Shell Encryption for Telnet Sessions

Monitoring User Sessions

Using Ping

Understanding How Ping Works

Executing Ping

Using Layer 2 Traceroute

Understanding Layer 2 Traceroute

Configuration Guidelines

Executing Layer 2 Traceroute

Using IP Traceroute

Understanding IP Traceroute

Executing IP Traceroute


Checking Port Status and Connectivity


This chapter describes how to check switch port status and connectivity on the Catalyst enterprise LAN switches.


Note For complete syntax and usage information for the commands used in this chapter, refer to the Catalyst 5000 Family Command Reference.


This chapter consists of these sections:

Checking Module Status

Checking Port Status

Checking Port Capabilities

Using Telnet

Using Secure Shell Encryption for Telnet Sessions

Monitoring User Sessions

Using Ping

Using Layer 2 Traceroute

Using IP Traceroute

Checking Module Status

The Catalyst enterprise LAN switches are multimodule systems. You can see what modules are installed, as well as the MAC address ranges and version numbers for each module, using the show module [mod_num] command. Specify a particular module number to see detailed information on that module.


Note For detailed information on the output of the show module command, see the Catalyst 5000 Family Command Reference.


This example shows how to check module status on a Catalyst 5000 family switch. The output shows that there are two supervisor engine modules (one in standby mode), four additional modules (including an RSM/VIP2 in slots 4 and 5 and a two-slot 10BASE-T Ethernet module in slots 9 and 10), and a LightStream 1010 ASP installed in the chassis.

Console> (enable) show module
Mod Slot Ports Module-Type               Model               Status
--- ---- ----- ------------------------- ------------------- --------
1   1    4     100BaseFX MMF Supervisor  WS-X5530            ok
2   2    4     100BaseFX MMF Supervisor  WS-X5530            standby
4   4          Route Switch Ext Port     
5   5    1     Route Switch              WS-X5302            ok
7   7    1     Network Analysis/RMON     WS-X5380            ok
8   8    1     MM OC-3 ATM               WS-X5155            ok
9   9          10/100BaseTX Ethernet Ext WS-X5238            
10  10   48    10/100BaseTX Ethernet     WS-X5238            ok
13  13         ASP/SRP                   

Mod Module-Name         Serial-Num
--- ------------------- --------------------
1                       00007451586
2                       00012114992
4  
5                       00007460757
7                       00008175475
8                       00003414855
9                       00011578014
10                      00011578014

Mod MAC-Address(es)                        Hw     Fw         Sw
--- -------------------------------------- ------ ---------- -----------------
1   00-e0-4f-ac-b0-00 to 00-e0-4f-ac-b3-ff 1.3    3.1.2      5.1(1)
1   00-e0-1e-9b-2e-00 to 00-e0-1e-9b-31-ff 1.3    3.1.2      5.1(1)
5   00-e0-1e-91-d5-14 to 00-e0-1e-91-d5-15 5.0    20.7       11.3(3a)WA4(5)
7   00-e0-14-10-18-00                      0.100  4.1.1      4.3(0.31)
8   00-e0-1e-a9-20-b9                      1.2    1.3        3.2(7)
10  00-50-0f-08-c3-f0 to 00-50-0f-08-c4-1f 0.1    5.3(1)B    5.1(1)

Mod Sub-Type Sub-Model Sub-Serial Sub-Hw
--- -------- --------- ---------- ------
1   NFFC     WS-F5521  0011462777 1.1
1   uplink   WS-U5538  0011464723 2.0
2   NFFC     WS-F5521  0008936340 1.1
2   uplink   WS-U5538  0007464204 2.0
Console> (enable)

This example shows how to check module status on a specific module:

Console> (enable) show module 4
Mod Slot Ports Module-Type               Model               Status
--- ---- ----- ------------------------- ------------------- --------
4   4    12    100BaseFX MM Ethernet     WS-X5201R           ok

Mod Module-Name         Serial-Num
--- ------------------- --------------------
4   Backbone Links      00007285650

Mod MAC-Address(es)                        Hw     Fw         Sw
--- -------------------------------------- ------ ---------- -----------------
4   00-e0-1e-38-48-cc to 00-e0-1e-38-48-d7 0.2    4.1(0.53-E 5.1(1)
Console> (enable)

Checking Port Status

You can see summary or detailed information on the switch ports using the show port [mod[/port]] command. To see summary information on all of the ports on the switch, enter the show port command with no arguments. Specify a particular module number to see information on the ports on that module only. Enter both the module number and the port number to see detailed information about the specified port.


Note For detailed information on the output of the show port command, see the Catalyst 5000 Family Command Reference publication for your switch.


This example shows how to see information on the ports on a specific module only:

Console> (enable) show port 3
Port  Name               Status     Vlan       Level  Duplex Speed Type
----- ------------------ ---------- ---------- ------ ------ ----- ------------
 3/1                     connected  10         normal   full  1000 1000BaseSX
 3/2                     connected  10         normal   full  1000 1000BaseSX
 3/3                     connected  20         normal   full  1000 1000BaseSX
 3/4                     connected  40         normal   full  1000 1000BaseSX
 3/5                     notconnect 1          normal   full  1000 No GBIC
 3/6                     notconnect 1          normal   full  1000 No GBIC

Port  Security Secure-Src-Addr   Last-Src-Addr     Shutdown Trap     IfIndex
----- -------- ----------------- ----------------- -------- -------- -------
 3/1  disabled                                     No       disabled 15     
 3/2  disabled                                     No       disabled 16     
 3/3  disabled                                     No       disabled 17     
 3/4  disabled                                     No       disabled 18     
 3/5  disabled                                     No       disabled 19     
 3/6  disabled                                     No       disabled 20     

Port   Send FlowControl    Receive FlowControl   RxPause TxPause Unsupported
       admin    oper       admin    oper                         opcodes
-----  -------- --------   -------- --------     ------- ------- -----------
 3/1   desired  on         desired  on           0       0       0
 3/2   desired  on         desired  on           0       0       0
 3/3   desired  on         desired  on           0       0       0
 3/4   desired  on         desired  on           0       0       0
 3/5   desired  off        off      off          0       0       0
 3/6   desired  off        off      off          0       0       0

Port  Status     Channel   Channel     Neighbor                  Neighbor
                 mode      status      device                    port
----- ---------- --------- ----------- ------------------------- ---------- 
 3/1  connected  off       not channel
 3/2  connected  off       not channel
 3/3  connected  off       not channel
 3/4  connected  off       not channel
 3/5  notconnect off       not channel
 3/6  notconnect off       not channel

Port  Align-Err  FCS-Err    Xmit-Err   Rcv-Err    UnderSize
----- ---------- ---------- ---------- ---------- ---------
 3/1           -          0          0          0         0
 3/2           -          0          0          0         0
 3/3           -          0          0          0         0
 3/4           -          0          0          0         0
 3/5           -          0          0          0         0
 3/6           -          0          0          0         0

Port  Single-Col Multi-Coll Late-Coll  Excess-Col Carri-Sen Runts     Giants
----- ---------- ---------- ---------- ---------- --------- --------- ---------
 3/1           0          0          0          0         0         0         0
 3/2           0          0          0          0         0         0         0
 3/3           0          0          0          0         0         0         0
 3/4           0          0          0          0         0         0         0
 3/5           0          0          0          0         0         0         0
 3/6           0          0          0          0         0         0         0

Last-Time-Cleared
--------------------------
Fri Apr 30 1999, 18:54:17
Console> (enable)

This example shows how to see information on an individual port:

Console> (enable) show port 2/1
Port  Name               Status     Vlan       Level  Duplex Speed Type
----- ------------------ ---------- ---------- ------ ------ ----- ------------
 2/1                     connected  trunk      normal   full  1000 1000BaseSX
Port  Security Secure-Src-Addr   Last-Src-Addr     Shutdown Trap     IfIndex
----- -------- ----------------- ----------------- -------- -------- -------
 2/1  disabled                                     No       disabled 9
Port   Send FlowControl    Receive FlowControl   RxPause TxPause Unsupported
       admin    oper       admin    oper                         opcodes
-----  -------- --------   -------- --------     ------- ------- -----------
 2/1   desired  off        off      off          0       0       0
Port  Status     Channel   Channel     Neighbor                  Neighbor
                 mode      status      device                    port
----- ---------- --------- ----------- ------------------------- ----------
 2/1  connected  auto      not channel
Port  Align-Err  FCS-Err    Xmit-Err   Rcv-Err    UnderSize
----- ---------- ---------- ---------- ---------- ---------
 2/1           -          0          0          0         0
Port  Single-Col Multi-Coll Late-Coll  Excess-Col Carri-Sen Runts     Giants
----- ---------- ---------- ---------- ---------- --------- --------- ---------
 2/1           0          0          0          0         0         0         0
Last-Time-Cleared
--------------------------
Tue Dec 8 1998, 13:26:01
Console> (enable)

Checking Port Capabilities

You can display the capabilities of any port in a switch using the show port capabilities [[mod][/port]] command.

This example shows you how to display the port capabilities for switch ports:

Console> (enable) show port capabilities 1
Model                    WS-X5509
Port                     1/1
Type                     100BaseTX
Speed                    100
Duplex                   half,full
Trunk encap type         ISL
Trunk mode               on,off,desirable,auto,nonegotiate
Channel                  1/1-2
Broadcast suppression    percentage(0-100)
Flow control             no
Security                 yes
Membership               static,dynamic
Fast start               yes
Rewrite                  no
--------------------------------------------------------------
Model                    WS-X5509
Port                     1/2
Type                     100BaseTX
Speed                    100
Duplex                   half,full
Trunk encap type         ISL
Trunk mode               on,off,desirable,auto,nonegotiate
Channel                  1/1-2
Broadcast suppression    percentage(0-100)
Flow control             no
Security                 yes
Membership               static,dynamic
Fast start               yes
Rewrite                  no
Console> (enable) show port capabilities 7/1
Model                    WS-X5014
Port                     7/1
Type                     10BaseT
Speed                    10
Duplex                   half,full
Trunk encap type         no
Trunk mode               off
Channel                  no
Broadcast suppression    percentage(0-100)
Flow control             no
Security                 yes
Membership               static,dynamic
Fast start               yes
Rewrite                  no
Console> (enable) show port capabilities 8
Model                    WS-X5155
Port                     8/1
Type                     OC3 MMF ATM
Speed                    155
Duplex                   full
Trunk encap type         LANE
Trunk mode               on
Channel                  no
Broadcast suppression    no
Flow control             no
Security                 no
Membership               static
Fast start               no
Rewrite                  no
Console> (enable)

Using Telnet

You can access the switch command-line interface (CLI) using Telnet. In addition, you can use Telnet from the switch to access other devices in the network. Up to eight simultaneous Telnet sessions are possible.

Before you can open a Telnet session to the switch, you must first set the IP address (and in some cases the default gateway) for the switch. For information about setting the IP address and default gateway, see Chapter 3, "Configuring the Switch IP Address and Default Gateway."

To use Telnet to connect to another device on the network from the switch, perform this task in privileged mode:

Task
Command

Open a Telnet session with a remote host.

telnet host [port]


This example shows how to connect from the switch to a remote host using Telnet:

Console> (enable) telnet labsparc
Trying 172.16.10.3...
Connected to labsparc.
Escape character is '^]'.

UNIX(r) System V Release 4.0 (labsparc)

login:

To change the logout timer value (the number of minutes after which an idle session is disconnected), perform this task in privileged mode:

Task
Command

Change the logout timer value (a timeout value of 0 prevents idle sessions from being disconnected automatically).

set logout timeout


This example shows how to set the logout timer value to 10 minutes:

Console> (enable) set logout 10
Sessions will be automatically logged out after 10 minutes of idle time.
Console> (enable) 

This example shows how to set the logout timer value to 0, preventing idle sessions from being disconnected automatically:

Console> (enable) set logout 0
Sessions will not be automatically logged out.
Console> (enable) 

Using Secure Shell Encryption for Telnet Sessions


Note To use the Secure Shell encryption feature commands you must be running an encryption image. Encryption commands are: set crypto key rsa, clear crypto key rsa, and show crypto key. See Chapter 33, "Working with System Software Images," for the software image naming conventions used for the encryption images.


The secure shell encryption feature provides security for Telnet sessions to the switch. Secure shell encryption is supported for remote logins to the switch only. Telnet sessions initiated from the switch cannot be encrypted. To use this feature, you must install the application on the client accessing the switch, and you must configure secure shell encryption on the switch.

The current implementation of Secure Shell encryption supports SSH version 1, both the DES and 3DES encryption methods, and can be used with RADIUS and TACACS+ authentication. To configure authentication with secure shell encryption, use the telnet keyword in the set authentication commands.


Note If you are using Kerberos to authenticate to the switch, you will not be able to use the secure shell encryption feature.


To enable secure shell encryption on the switch, perform this task in privileged mode:

Task
Command

Create the RSA host key.

set crypto key rsa nbits [force]


This example shows how to create the RSA host key:

Console> (enable) set crypto key rsa 1024
Generating RSA keys.... [OK]
Console> (enable)

The nbits value specifies the RSA key size. Valid key size range is 512 to 2048 bits. A key size with a larger number provides higher security but takes longer to generate.

Monitoring User Sessions

You can display the currently active user sessions on the switch using the show users command. The command output displays all active console port and Telnet sessions on the switch.

To display the active user sessions on the switch, perform this task in privileged mode:

Task
Command

Display the currently active user sessions on the switch.

show users [noalias]


This example shows the output of the show users command when local authentication is enabled for console and Telnet sessions (the asterisk [*] indicates the current session):

Console> (enable) show users
  Session  User             Location
  -------- ---------------- -------------------------
  console  
  telnet                    sam-pc.bigcorp.com
* telnet                    jake-mac.bigcorp.com
Console> (enable) 

This example shows the output of the show users command when TACACS+ authentication is enabled for console and Telnet sessions:

Console> (enable) show users
  Session  User             Location
  -------- ---------------- -------------------------
  console  sam
  telnet   jake             jake-mac.bigcorp.com
  telnet   tim              tim-nt.bigcorp.com
* telnet   suzy             suzy-pc.bigcorp.com
Console> (enable)

This example shows how to display information about user sessions using the noalias keyword to display the IP addresses of connected hosts:

Console> (enable) show users noalias
  Session  User             Location
  -------- ---------------- -------------------------
  console  
  telnet                    10.10.10.12
* telnet                    10.10.20.46
Console> (enable)

To disconnect an active user session, perform this task in privileged mode:

Task
Command

Disconnect an active user session on the switch.

disconnect {console | ip_addr}


This example shows how to disconnect an active console port session and an active Telnet session:

Console> (enable) show users
  Session  User             Location
  -------- ---------------- -------------------------
  console  sam
  telnet   jake             jake-mac.bigcorp.com
  telnet   tim              tim-nt.bigcorp.com
* telnet   suzy             suzy-pc.bigcorp.com
Console> (enable) disconnect console
Console session disconnected.				
Console> (enable) disconnect tim-nt.bigcorp.com
Telnet session from tim-nt.bigcorp.com disconnected. (1)
Console> (enable) show users
  Session  User             Location
  -------- ---------------- -------------------------
  telnet   jake             jake-mac.bigcorp.com
* telnet   suzy             suzy-pc.bigcorp.com
Console> (enable)

Using Ping

These sections describe how to use IP ping:

Understanding How Ping Works

Executing Ping

Understanding How Ping Works

You can use IP ping to test connectivity to remote hosts. If you attempt to ping a host in a different IP subnetwork, you must define a static route to the network or configure a router to route between those subnets.

The ping command is configurable from normal executive and privileged executive mode. In normal executive mode, the ping command supports the -s parameter, which allows you to specify the packet size and packet count. In privileged executive mode, the ping command allows you to specify the packet size, packet count, and the wait time.

Table 21-1 lists the ping default values.

Table 21-1 Ping Default Values

Ping
Ping-s
Number of Packets

5

0=continuous ping

Packet Size

56

56

Wait Time

2

2

Source Address

Host IP Address

-


Ping will return one of the following responses:

Normal response—The normal response (hostname is alive) occurs in 1 to 10 seconds, depending on network traffic.

Destination does not respond—If the host does not respond, a no answer message is returned.

Unknown host—If the host does not exist, an unknown host message is returned.

Destination unreachable—If the default gateway cannot reach the specified network, a destination unreachable message is returned.

Network or host unreachable—If there is no entry in the route table for the host or network, a network or host unreachable message is returned.

To stop a ping in progress, press Ctrl-C.

Executing Ping

To ping another device on the network from the switch, perform one of these tasks in normal or privileged mode:

Task
Command

Ping a remote host.

ping host

Ping a remote host using ping options.

ping -s host [packet_size] [packet_count]


This example shows how to ping a remote host from normal executive mode:

Console> ping labsparc
labsparc is alive
Console>ping 72.16.10.3
12.16.10.3 is alive
Console> 

This example shows how to ping a remote host using the ping -s option:

Console> ping -s 12.20.5.3 800 10
PING 12.20.2.3: 800 data bytes
808 bytes from 12.20.2.3: icmp_seq=0. time=2 ms
808 bytes from 12.20.2.3: icmp_seq=1. time=3 ms
808 bytes from 12.20.2.3: icmp_seq=2. time=2 ms
808 bytes from 12.20.2.3: icmp_seq=3. time=2 ms
808 bytes from 12.20.2.3: icmp_seq=4. time=2 ms
808 bytes from 12.20.2.3: icmp_seq=5. time=2 ms
808 bytes from 12.20.2.3: icmp_seq=6. time=2 ms
808 bytes from 12.20.2.3: icmp_seq=7. time=2 ms
808 bytes from 12.20.2.3: icmp_seq=8. time=2 ms
808 bytes from 12.20.2.3: icmp_seq=9. time=3 ms

----17.20.2.3 PING Statistics----
10 packets transmitted, 10 packets received, 0% packet loss
round-trip (ms)  min/avg/max = 2/2/3
Console> 

This example shows how to enter a ping command in privileged mode specifying the number of packets, the packet size, and the timout period:

Console> (enable) ping
Target IP Address []: 12.20.5.19
Number of Packets [5]: 10
Datagram Size [56]: 100
Timeout in seconds [2]: 10
Source IP Address [12.20.2.18]: 12.20.2.18
!!!!!!!!!!

----12.20.2.19 PING Statistics----
10 packets transmitted, 10 packets received, 0% packet loss
round-trip (ms)  min/avg/max = 1/1/1
Console> (enable) 

Using Layer 2 Traceroute

These sections describe how to use Layer 2 traceroute:

Understanding Layer 2 Traceroute

Configuration Guidelines

Executing Layer 2 Traceroute

Understanding Layer 2 Traceroute

The Layer 2 traceroute utility allows you to identify the physical path that a packet takes when going from a source to a destination. The Layer 2 traceroute utility determines the path by looking at the forwarding engine tables of the switches in the path.

Information is displayed about all Catalyst 5000 family switches that are in the path from the source to the destination.

Configuration Guidelines

Follow these configuration guidelines when using the Layer 2 traceroute utility:

The Layer 2 traceroute utility works for unicast traffic only.

CDP must be enabled on all of the Catalyst 5000 family switches in the network. (See Chapter 22, "Configuring CDP" for information about enabling CDP.) If any devices in the path are transparent to CDP, the l2trace command will not trace the path through those devices.

You can use this utility from a switch that is not in the Layer 2 path between the source and the destination; however, all of the switches in the path, including the source and destination, must be reachable from the switch.

All switches in the path must be reachable from each other.

You can trace a Layer 2 path by specifying the source and destination IP addresses (or IP aliases) or the MAC addresses. If the source and destination belong to multiple VLANs and you specify MAC addresses, you can also specify a VLAN.

The source and destination switches must belong in the same VLAN.

The maximum number of hops an l2trace command query tries is 10; this number includes hops involved in source tracing.

Layer 2 traceroute does not work with Token Ring VLANs, or when multiple devices are attached to one port through hubs, or when there are multiple neighbors on a port.

Executing Layer 2 Traceroute

To identify a Layer 2 path, perform one of these tasks in privileged mode.

Task
Command

(Optional) Trace a Layer 2 path using MAC addresses.

l2trace {src-mac-addr} {dest-mac-addr} [vlan] [detail]

(Optional) Trace a Layer 2 path using IP addresses or IP aliases.

l2trace {src-ip-addr} {dest-ip-addr} [detail]

This example shows the source and destination MAC addresses specified, with no VLAN specified, and the detail option specified. For each Catalyst 5000 family switch found in the path, the output shows the device type, device name, device IP address, in port name, in port speed, in port duplex mode, out port name, out port speed, and out port duplex mode.

Console> (enable) l2trace 00-01-22-33-44-55 10-22-33-44-55-66 detail

l2trace vlan number is 10. 

00-01-22-33-44-55 found in C5500 named wiring-1 on port 4/1 10Mb half duplex 
C5500:wiring-1:192.168.242.10:4/1 10Mb half duplex -> 5/2 100MB full duplex 
C5000:backup-wiring-1:192.168.242.20:1/1 100Mb full duplex -> 3/1 100MB full duplex 
C5000:backup-core-1:192.168.242.30:4/1 100 MB full duplex -> 1/1 100MB full duplex 
C6000:core-1:192.168.242.40:1/1 100MB full duplex -> 2/1 10MB half duplex. 
10-22-33-44-55-66 found in C6000 named core-1 on port 2/1 10MB half duplex. 
Console> (enable)

Using IP Traceroute

These sections describe how to use IP traceroute:

Understanding IP Traceroute

Executing IP Traceroute

Understanding IP Traceroute

You can use IP traceroute to identify the path that packets take through the network on a hop-by-hop basis. The command output displays all network layer (Layer 3) devices, such as routers, that the traffic passes through on the way to the destination.

Switches can participate as the source or destination of the traceroute command but will not appear as a hop in the traceroute command output.

The traceroute command uses the time-to-live (TTL) field in the IP header to cause routers and servers to generate specific return messages. Traceroute starts by sending a User Datagram Protocol (UDP) datagram to the destination host with the TTL field set to 1. If a router finds a TTL value of 1 or 0, it drops the datagram and sends back an Internet Control Message Protocol (ICMP) time-exceeded message to the sender. The traceroute facility determines the address of the first hop by examining the source address field of the ICMP time-exceeded message.

To identify the next hop, traceroute sends a UDP packet with a TTL value of 2. The first router decrements the TTL field by 1 and sends the datagram to the next router. The second router sees a TTL value of 1, discards the datagram, and returns the time-exceeded message to the source. This process continues until the TTL is incremented to a value large enough for the datagram to reach the destination host (or until the maximum TTL is reached).

To determine when a datagram reaches its destination, traceroute sets the UDP destination port in the datagram to a very large value that the destination host is unlikely to be using. When a host receives a datagram with an unrecognized port number, it sends an ICMP port unreachable error to the source. This message indicates to the traceroute facility that it has reached the destination.

Executing IP Traceroute

To trace the path that packets take through the network, perform this task in privileged mode:

Task
Command

Execute IP traceroute to trace the Layer 3 path that packets take through the network.

traceroute [-n] [-w wait_time] [-i initial_ttl] [-m max_ttl] [-p dest_port] [-q nqueries] [-t tos] host [data_size]


This example shows how to use the traceroute command:

Console> (enable) traceroute 10.1.1.100
traceroute to 10.1.1.100 (10.1.1.100), 30 hops max, 40 byte packets
 1 10.1.1.1 (10.1.1.1)  1 ms  2 ms  1 ms
 2 10.1.1.100 (10.1.1.100)  2 ms  2 ms  2 ms
Console> (enable)

This example shows how to perform a traceroute with six queries to each hop with packets of 1400 bytes each:

Console> (enable) traceroute -q 6 10.1.1.100 1400
traceroute to 10.1.1.100 (10.1.1.100), 30 hops max, 1440 byte packets
 1 10.1.1.1 (10.1.1.1)  2 ms  2 ms  2 ms  1 ms  2 ms  2 ms
 2 10.1.1.100 (10.1.1.100)  2 ms  4 ms  3 ms  3 ms  3 ms  3 ms
Console> (enable)