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This chapter describes how to use the command-line interface (CLI) to configure Ethernet, Fast Ethernet, and Gigabit Ethernet switching on the Catalyst 6000 family switches. The configuration tasks in this chapter apply to Ethernet, Fast Ethernet, and Gigabit Ethernet switching modules, as well as to the uplink ports on the supervisor engine.
This chapter consists of these sections:
The Catalyst 6000 family switches support simultaneous, parallel connections between Ethernet segments. Switched connections between Ethernet segments last only for the duration of the packet. New connections can be made between different segments for the next packet.
The Catalyst 6000 family switches solve congestion problems caused by high-bandwidth devices and a large number of users by assigning each device (for example, a server) to its own 10-, 100-, or 1000-Mbps segment. Because each Ethernet port on the switch represents a separate Ethernet segment, servers in a properly configured switched environment achieve full access to the bandwidth.
Because collisions are a major bottleneck in Ethernet networks, an effective solution is full-duplex communication, which is an option for any 10- or 100-Mbps port on a Catalyst 6000 family switch (Gigabit Ethernet ports are always full duplex). Normally, Ethernet operates in half-duplex mode, which means that stations can either receive or transmit. In full-duplex mode, two stations can transmit and receive at the same time. When packets can flow in both directions simultaneously, effective Ethernet bandwidth doubles to 20 Mbps for 10-Mbps ports and to 200 Mbps for Fast Ethernet ports. Gigabit Ethernet ports on Catalyst 6000 family switches are full-duplex only (2 Gbps effective bandwidth).
Each Ethernet port on a Catalyst 6000 family switch can connect to a single workstation or server, or to a hub through which workstations or servers connect to the network.
Ports on a typical Ethernet hub all connect to a common backplane within the hub, and the bandwidth of the network is shared by all devices attached to the hub. If two stations establish a session that uses a significant level of bandwidth, the network performance of all other stations attached to the hub is degraded.
To reduce degradation, the switch treats each port as an individual segment. When stations on different ports need to communicate, the switch forwards frames from one port to the other at wire speed to ensure that each session receives full bandwidth.
To switch frames between ports efficiently, the switch maintains an address table. When a frame enters the switch, it associates the MAC address of the sending station with the port on which it was received.
The address table can store at least 16,000 address entries without flooding any entries. The switch uses an aging mechanism, defined by a configurable aging timer, so if an address remains inactive for a specified number of seconds, it is removed from the address table.
Port negotiation exchanges flow-control parameters, remote fault information, and duplex information. Configure port negotiation with the set port negotiation command. Port negotiation is enabled by default.
The ports on both ends of a 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 4-1 shows the four possible port negotiation configurations and the resulting link status for each configuration.
| 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 port. 2Far End refers to the port at the other end of the link. |
Table 4-2 shows the Ethernet, Fast Ethernet, and Gigabit Ethernet default configuration.
| Feature | Default Value |
|---|---|
Port enable state | All ports are enabled |
Port name | None |
Duplex mode |
|
Flow control (Gigabit Ethernet) | Flow control set to off for receive (Rx) and desired for transmit (Tx) |
Flow control (other Ethernet) | Flow control set to off for receive (Rx); transmit (Tx) not supported |
Spanning-Tree Protocol (STP) | Enabled for VLAN 1 |
Native VLAN | VLAN 1 |
Port VLAN cost |
|
EtherChannel | Disabled on all Ethernet ports |
Jumbo frames | Disabled on all Gigabit Ethernet ports |
These sections describe how to configure Ethernet, Fast Ethernet, and Gigabit Ethernet switching on the Catalyst 6000 family switches:
You can set port names on Ethernet, Fast Ethernet, and Gigabit Ethernet switching modules to facilitate switch administration.
To set the port name, perform this task in privileged mode:
| Task | Command |
|---|---|
Step 1 Set a port name. | set port name mod_num/port_num [name_string] |
Step 2 Verify the port name is configured. | show port [mod_num[/port_num]] |
This example shows how to set the name for ports 1/1 and 1/2 and how to verify that the port names are configured correctly:
Console> (enable) set port name 1/1 Router Connection Port 1/1 name set. Console> (enable) set port name 1/2 Server Link Port 1/2 name set. Console> (enable) show port 1 Port Name Status Vlan Duplex Speed Type ----- ------------------ ---------- ---------- ------ ----- ------------ 1/1 Router Connection connected trunk full 1000 1000BaseSX 1/2 Server Link connected trunk full 1000 1000BaseSX <...output truncated...> Last-Time-Cleared -------------------------- Wed Jun 16 1999, 16:25:57 Console> (enable)
You can configure the port speed on 10/100-Mbps Ethernet switching modules. Use the auto keyword to autonegotiate the port's speed and duplex mode with the neighboring port.
To set the port speed for a 10/100-Mbps port, perform this task in privileged mode:
| Task | Command |
|---|---|
Step 1 Set the port speed of a 10/100-Mbps Fast Ethernet port. | set port speed mod num/port num {10 | 100 | auto} |
Step 2 Verify that the speed of the port is configured correctly. | show port [mod_num[/port_num]] |
This example shows how to set the port speed to 100 Mbps on port 2/2:
Console> (enable) set port speed 2/2 100 Port 2/2 speed set to 100 Mbps. Console> (enable)
This example shows how to make port 2/1 autonegotiate speed and duplex with the neighboring port:
Console> (enable) set port speed 2/1 auto Port 2/1 speed set to auto-sensing mode. Console> (enable)
You can set the port duplex mode to full or half duplex for Ethernet and Fast Ethernet ports.
To set the duplex mode of a port, perform this task in privileged mode:
| Task | Command |
|---|---|
Step 1 Set the duplex mode of a port. | set port duplex mod num/port num {full | half} |
Step 2 Verify that the duplex mode of the port is configured correctly. | show port [mod_num[/port_num]] |
This example shows how to set the duplex mode to half duplex on port 2/1:
Console> (enable) set port duplex 2/1 half Port 2/1 set to half-duplex. Console> (enable)
Gigabit Ethernet ports on the Catalyst 6000 family switches use flow control to inhibit the transmission of packets to the port for a period of time; other Ethernet ports use flow control to respond to flow-control requests.
If a Gigabit Ethernet port receive buffer becomes full, the port transmits a "pause" packet that tells remote ports to delay sending more packets for a specified period of time. All Ethernet ports (1000 Mbps, 100 Mbps, and 10 Mbps) can receive and act upon "pause" packets from other devices.
Enter the set port flow control command to configure flow control on ports. Table 4-3 lists the set port flowcontrol command keywords and describes their functions.
| Keywords | Function |
|---|---|
receive on | The port uses flow control dictated by the neighboring port. |
receive desired | The port uses flow control if the neighboring port uses it and does not use flow control if the neighbor port does not use it. |
receive off | The port does not use flow control, regardless of whether flow control is requested by the neighboring port. |
send on1 | The port sends flow-control frames to the neighboring port. |
send desired1 | The port sends flow-control frames to the v port if the neighbor port asks to use flow control. |
send off1 | The port does not send flow-control frames to the neighboring port. |
| 1Supported only on Gigabit Ethernet ports. |
To configure flow control, perform this task in privileged mode:
| Task | Command |
|---|---|
Step 1 Set the flow-control parameters. | set port flowcontrol mod_num/port_num {receive | send} {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 3/1 send on Port 3/1 will send flowcontrol to far end. Console> (enable) set port flowcontrol 3/1 receive on Port 3/1 will require far end to send flow control Console> (enable) show port flowcontrol Port Send-Flowcontrol Receive-Flowcntl RxPause TxPause Admin Oper Admin Oper ----- ---------------- ---------------- ------- ------- 3/1 on disagree on disagree 0 0 3/2 off off off off 0 0 3/3 desired on desired off 10 10 Console> (enable)
To enable port negotiation, perform this task in privileged mode:
| Task | Command |
|---|---|
Step 1 Enable port negotiation. | set port negotiation mod_num/port_num enable |
Step 2 Verify the port negotiation configuration. | show port negotiation [mod_num/port_num] |
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, perform this task in privileged mode:
| Task | Command |
|---|---|
Step 1 Disable port negotiation. | set port negotiation mod_num/port_num disable |
Step 2 Verify the port negotiation configuration. | show port negotiation [mod_num/port_num] |
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)
When you enter clear config all or during a configuration loss, all ports collapse into VLAN 1 causing security and network instability problems. The set default portstatus command allows you to change the default port status from enabled to disabled. This command disables all ports and blocks the traffic flowing through the ports during configuration loss situations. You can then manually enable the ports.
After you enter the set default portstatus command, you must reset the system so the new configuration can take effect. The new configuration is not saved in NVRAM, it is stored in a chassis ID PROM. With the port enable state disabled, the system configuration is not cleared when you enter the clear config all command. Additionally, when you replace a supervisor engine, since the configuration is saved in the chassis ID PROM, there is no need to reconfigure the new supervisor engine.
To change the port enable state, perform this task in privileged mode:
| Task | Command |
|---|---|
Step 1 Change the port enable state. | set default portstatus {enable | disable} |
Step 2 Display the port enable state. | show default |
This example shows how to change the default port enable state from enabled to disabled:
Console> (enable)set default portstatus disableDefault port status set to disable.Console> (enable)
This example shows how to display the port enable state:
Console> (enable)show defaultportstatus: disableConsole> (enable)
A port is in errdisable state if it is enabled in NVRAM, but is disabled at runtime by any process. For example, if UniDirectional Link Detection (UDLD) detects a unidirectional link, the port shuts down at runtime. However, because the NVRAM configuration for the port is enabled (you have not disabled the port), the port status is shown as errdisable.
Once a port is in the errdisable state, you have to manually reenable it. The errdisable timeout feature allows you to configure a timeout period for ports in errdisable state; the ports are reenabled automatically eliminating the need to manually reenable all the errdisabled ports.
A port enters errdisable state for the following reasons (these appear as configuration options with the set errdisable-timeout enable command):
1. Channel misconfiguration
2. Duplex mismatch
3. BPDU port-guard
4. UDLD
5. Other (reasons other than the above)
6. All (apply errdisable timeout to all reasons)
You can enable or disable errdisable timeout for each of the above listed reasons. The ports in errdisable state for reasons other than 1 through 4 are considered "other." If you specify "other," all ports errdisabled by causes other than 1 through 4 are enabled for errdisable timeout. If you specify "all," all ports errdisabled for any reason are enabled for errdisable timeout.
The errdisable feature is disabled by default. The default interval for enabling a port is 300 seconds. The allowable interval range is 30 to 86400 seconds (30 seconds to 24 hours).
This example shows how to enable errdisable timeout for BPDU guard causes:
Console>(enable)set errdisable-timeout enable bpdu-guardSuccessfully enabled errdisable-timeout for bpdu-guard.Console> (enable) Console>(enable)
This example shows how to enable errdisable timeout for all causes:
Console> (enable) set errdisable-timeout enable all
Successfully enabled errdisable-timeout for all.
Console> (enable)
This example shows how to set the errdisable timeout interval to 450 seconds:
Console>(enable)set errdisable-timeout interval 450 Successfully set errdisable timeout to 450 seconds.Console>(enable)
This example shows how to display the errdisable timeout configuration:
Console>(enable)show errdisable-timeoutErrDisable Reason Timeout Status------------------- ------------bpdu-guard Enablechannel-misconfig Disableduplex-mismatch Enableudld Enableother DisableInterval: 300 secondsPorts that will be enabled at the next timeout:Port ErrDisable Reason----- -----------------3/1 udld3/8 bpdu-guard6/5 udld7/24 duplex-mismatchConsole>(enable)
Enabling the jumbo frames feature on a port allows the port to switch large frames or jumbo frames. This feature is useful in optimizing server-to-server performance. The default maximum transmission unit (MTU) frame size is 1548 bytes for all Ethernet, Fast Ethernet, and Gigabit Ethernet ports. Enabling the jumbo frames feature on a port increases the MTU to 9216 bytes.
Follow these guidelines to enable the jumbo frame feature on a per-port basis:
To enable jumbo frames on a Gigabit Ethernet port, perform this task in privileged mode:
| Task | Command |
|---|---|
Step 1 Enable jumbo frames. | set port jumbo mod_num/port_num enable |
Step 2 Verify the port configuration. | show port jumbo |
This example shows how to enable jumbo frames on a port and verify the configuration:
Console> (enable) set port jumbo 2/1 enable Jumbo frames enabled on port 2/1 Console> (enable) show port jumbo Jumbo frames MTU size is 9216 bytes Jumbo frames enabled on port(s) 2/1
To disable jumbo frames on a Gigabit Ethernet port, perform this task in privileged mode:
| Task | Command |
|---|---|
Step 1 Disable jumbo frames. | set port jumbo mod_num/port_num disable |
Step 2 Verify the port configuration. | show port jumbo |
This example shows how to disable jumbo frames on a port:
Console> (enable) set port jumbo 2/1 disable Jumbo frames disabled on port 2/1 Console> (enable)
Use the ping and traceroute commands to test connectivity.
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 |
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)
Posted: Mon Feb 21 16:14:08 PST 2000
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