Catalyst 5000 Family Software Configuration Guide (6.3 and 6.4) - Configuring Gigabit Ethernet Switching [Cisco Catalyst 5000 Series Switches]

Table Of Contents

Configuring Gigabit Ethernet Switching

Understanding How Gigabit Ethernet Works

Understanding How Gigabit Ethernet Flow Control Works

Overview of Flow Control

Sending and Receiving Pause Frames

Using Flow-Control Keywords

Understanding How Port Negotiation Works

Default Gigabit Ethernet Configuration

Configuring Gigabit Ethernet

Setting the Port Name

Setting the Port Priority Level

Configuring Flow Control on Gigabit Ethernet Ports

Configuring Port Negotiation on Gigabit Ethernet Ports

Changing the Default Port Enable State

Configuring a Timeout Period for Ports in Errdisable State

Checking Connectivity

Configuring Gigabit Ethernet Switching

This chapter describes how to configure Gigabit Ethernet switching on the Catalyst enterprise LAN switches. The configuration tasks in this chapter apply to Gigabit Ethernet switching modules, fixed-configuration switches, and uplink ports on the supervisor engine.

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:

•Understanding How Gigabit Ethernet Works

•Default Gigabit Ethernet Configuration

•Configuring Gigabit Ethernet

Understanding How Gigabit Ethernet Works

These sections describe how Gigabit Ethernet works:

•Understanding How Gigabit Ethernet Flow Control Works

•Understanding How Port Negotiation Works

Understanding How Gigabit Ethernet Flow Control Works

These sections describe how flow control works:

•Overview of Flow Control

•Sending and Receiving Pause Frames

•Using Flow-Control Keywords

Overview of Flow Control

Flow control is a feature that Gigabit Ethernet ports use to inhibit the transmission of incoming packets. If a buffer on a Gigabit Ethernet port runs out of space, the port transmits a special packet that requests remote ports to delay sending packets for a period of time. This special packet is called a pause frame.

Sending and Receiving Pause Frames

All Catalyst Gigabit Ethernet ports can receive and process pause frames from other devices. However, not all Catalyst Gigabit Ethernet ports can transmit pause frames to other devices.

Table 6-1 identifies the Catalyst Gigabit Ethernet switches, modules, and ports that can transmit pause frames to other devices.

Table 6-1 Send Capability by Switch Type, Module, and Ports

Switch Type

Module

Ports

Send

Catalyst 5000

All modules except WS-X5410

All ports except WS-X5410

Yes

Catalyst 5000

WS-X5410

Uplink ports

No

Catalyst 5000

WS-X5410

Oversubscribed ports

Yes

Using Flow-Control Keywords

Table 6-2 describes guidelines for using different configurations of the send and receive keywords with the set port flowcontrol command.

Table 6-2 Send and Receive Keyword Configurations

Configuration

Description

send on

Enables a local port to send pause frames to a remote port. Use send on when a remote port is set to receive on or receive desired.

send off

Prevents a local port from sending pause frames to a remote port. Use send off when a remote port is set to receive off or receive desired.

send desired

Indicates preference to send pause frames, but autonegotiates flow control. You can use send desired when a remote port is set to receive on, receive off, or receive desired.

receive on

Enables a local port to process pause frames that a remote port sends. Use receive on when a remote port is set to send on or send desired.

receive off

Prevents a local port from processing pause frames. Use receive off when a remote port is set to send off or send desired.

receive desired

Indicates preference to process pause frames, but autonegotiates flow control. You can use receive desired when a remote port is set to send on, send off, or send desired.

Understanding How Port Negotiation Works

Caution Unlike autonegotiation with 10/100 Fast Ethernet, Gigabit Ethernet port negotiation does not negotiate port speed. You cannot disable port negotiation on Gigabit Ethernet ports using the set port speed command.

Note Port negotiation is not supported on 1000BASE-T Gigabit Ethernet ports.

With Gigabit Ethernet ports, port negotiation is used to exchange flow-control parameters, remote fault information, and duplex information (even though Cisco Gigabit Ethernet ports only support full-duplex mode).

You can configure port negotiation using the set port negotiation command on Gigabit Ethernet ports. Gigabit Ethernet port negotiation is enabled by default.

The ports on both ends of a Gigabit Ethernet link must have the same setting. The link will not come up if the ports at each end of the link are set inconsistently (port negotiation enabled on one port and disabled on the other). Table 6-3 shows the four possible port negotiation configurations for a Gigabit Ethernet link and the resulting link status for each configuration.

Table 6-3 Gigabit Ethernet Port Negotiation Configuration and Possible Link States

Port Negotiation State

Link Status

Near End¹

Far End²

Near End

Far End

Off

Off

Up

Up

On

On

Up

Up

Off

On

Up

Down

On

Off

Down

Up

¹Near End refers to the local Gigabit EtherChannel module port.

²Far End refers to the remote port at the other end of the Gigabit link.

Note On 1000BASE-T Gigabit Ethernet ports, you cannot configure speed or duplex mode. 1000BASE-T ports only operate in the default configuration where the speed is 1000 and duplex mode is full. You cannot disable autonegotiation. On 1000BASE-T port, you can configure flow control and enable or disable a port. To determine which features a 1000BASE-T Gigabit Ethernet port supports, enter the show port capabilities mod command.

Default Gigabit Ethernet Configuration

Table 6-4 shows the Gigabit Ethernet default configuration.

Table 6-4 Gigabit Ethernet Default Configuration

Feature

Default Value

Port enable state

All ports are enabled

Port name

None

Port priority

Normal

Duplex mode

Full duplex

Flow control

•Oversubscribed Gigabit Ethernet ports (ports 3-18 on WS-X4418-GB): Flow control set to desired for receive (Rx) and on for transmit (Tx)

•All others: Flow control set to off for receive (Rx) and desired for transmit (Tx)

Port negotiation

Enabled

Spanning Tree Protocol

Enabled for VLAN 1

Native VLAN

VLAN 1

Spanning tree port cost

4

Gigabit EtherChannel

Disabled on all Gigabit Ethernet ports (auto mode)

Configuring Gigabit Ethernet

These sections describe how to configure Gigabit Ethernet switching ports on the Catalyst enterprise LAN switches:

•Setting the Port Name

•Setting the Port Priority Level

•Configuring Flow Control on Gigabit Ethernet Ports

•Configuring Port Negotiation on Gigabit Ethernet Ports

•Changing the Default Port Enable State

•Configuring a Timeout Period for Ports in Errdisable State

•Checking Connectivity

Note For information on configuring Gigabit EtherChannel, refer to Chapter 7, "Configuring Fast EtherChannel and Gigabit EtherChannel."

Setting the Port Name

You can assign names to the ports on Gigabit Ethernet modules to facilitate switch administration.

To assign a name to a port, perform this task in privileged mode:

Task

Command

Step 1

Assign a name to a port.

set port name mod/port [name_string]

Step 2

Verify that the port name is configured.

show port [mod[/port]]

This example shows how to set the name for ports 2/1 and 2/2 and how to verify that the port names are configured correctly:
Console> (enable) set port name 2/1 Backbone Connection
Port 2/1 name set.
Console> (enable) set port name 2/2 Wiring Closet
Port 2/2 name set.
Console> (enable) show port 2
Port  Name               Status     Vlan       Level  Duplex Speed Type
----- ------------------ ---------- ---------- ------ ------ ----- ------------
 2/1  Backbone Connectio connected  trunk      normal   full  1000 1000BaseSX
 2/2  Wiring Closet      notconnect 1          normal   full  1000 1000BaseSX
<...output truncated...>
Last-Time-Cleared
--------------------------
Tue Dec 22 1998, 13:42:04
Console> (enable)
Setting the Port Priority Level

You can configure the priority level for each port. When two ports simultaneously request access to the switching bus, the switch uses the priority level to determine the order in which the ports get access.

To set the port priority level, perform this task in privileged mode:

Task

Command

Step 1

Configure the priority level for a port.

set port level mod/port {normal | high}

Step 2

Verify that the port priority level is configured correctly.

show port [mod[/port]]

This example shows how to set the port priority level to high for port 2/1 and verify that the port priority is configured correctly:
Console> (enable) set port level 2/1 high
Port 2/1 level set to high.
Console> (enable) show port 2/1
Port  Name               Status     Vlan       Level  Duplex Speed Type
----- ------------------ ---------- ---------- ------ ------ ----- ------------
 2/1  Backbone Connectio connected  trunk      high     full  1000 1000BaseSX
<...output truncated...>
Last-Time-Cleared
--------------------------
Tue Dec 22 1998, 13:42:04
Console> (enable)
Configuring Flow Control on Gigabit Ethernet Ports

To configure flow control on a Gigabit Ethernet port, perform this task in privileged mode:

Task

Command

Step 1

Set the flow-control parameters on a Gigabit Ethernet port.

set port flowcontrol {receive | send} mod/port {off | on | desired}

Step 2

Verify the flow-control configuration.

show port flowcontrol

This example shows how to turn transmit and receive flow control on and how to verify the flow-control configuration:
Console> (enable) set port flowcontrol send 2/1 on
Port 2/1 flow control send administration status set to on
(port will send flowcontrol to far end)
Console> (enable) set port flowcontrol receive 2/1 on
Port 2/1 flow control receive administration status set to on
(port will require far end to send flowcontrol)
Console> (enable) show port flowcontrol 2/1
Port   Send FlowControl    Receive FlowControl   RxPause TxPause Unsupported
       admin    oper       admin    oper                         opcodes
-----  -------- --------   -------- --------     ------- ------- -----------
 2/1   on       on         on       on           0       0       0
Console> (enable)
Configuring Port Negotiation on Gigabit Ethernet Ports

Note You cannot configure port negotiation on 1000BASE-T Gigabit Ethernet ports in this release.

To enable port negotiation on a 1000BASE-X Gigabit Ethernet port, perform this task in privileged mode:

Task

Command

Step 1

Enable Gigabit Ethernet port negotiation.

set port negotiation mod/port enable

Step 2

Verify the port negotiation configuration.

show port negotiation [mod/port]

This example shows how to enable port negotiation and verify the configuration:
Console> (enable) set port negotiation 2/1 enable
Port 2/1 negotiation enabled
Console> (enable) show port negotiation 2/1
Port   Link Negotiation
-----  ----------------
 2/1   enabled
Console> (enable)
To disable port negotiation on a 1000BASE-X Gigabit Ethernet port, perform this task in privileged mode:

Task

Command

Step 1

Disable Gigabit Ethernet port negotiation.

set port negotiation mod/port disable

Step 2

Verify the port negotiation configuration.

show port negotiation [mod/port]

This example shows how to disable port negotiation and verify the configuration:
Console> (enable) set port negotiation 2/1 disable
Port 2/1 negotiation disabled
Console> (enable) show port negotiation 2/1
Port   Link Negotiation
-----  ----------------
 2/1   disabled
Console> (enable)
Changing the Default Port Enable State

For information on changing the default port enable state, see Chapter 5, "Configuring Ethernet and Fast Ethernet Switching."

Configuring a Timeout Period for Ports in Errdisable State

For information on configuring a timeout period for ports in errdisable state, see Chapter 5, "Configuring Ethernet and Fast Ethernet Switching."

Checking Connectivity

Note For more detailed information on checking connectivity, see Chapter 21, "Checking Port Status and Connectivity."

Use the ping and traceroute commands to test connectivity out Gigabit Ethernet ports.

To check connectivity out a port, perform this task in privileged mode:

Task

Command

Step 1

Ping a remote host that is located out the port you want to test.

ping [-s] host [packet_size] [packet_count]

Step 2

Trace the hop-by-hop route of packets from the switch to a remote host located out the port you want to test.

traceroute host

Step 3

If the host is unresponsive, check the IP address and default gateway configured on the switch.

show interface
show ip route

This example shows how to ping a remote host and how to trace the hop-by-hop path of packets through the network using traceroute:
Console> (enable) ping somehost
somehost is alive
Console> (enable) traceroute somehost
traceroute to somehost.company.com (10.1.2.3), 30 hops max, 40 byte packets
 1 engineering-1.company.com (173.31.192.206) 2 ms 1 ms 1 ms
 2 engineering-2.company.com (173.31.196.204) 2 ms 3 ms 2 ms
 3 gateway_a.company.com (173.16.1.201) 6 ms 3 ms 3 ms
 4 somehost.company.com (10.1.2.3) 3 ms * 2 ms
Console> (enable)