Why do Cisco Catalyst 4948 (WS-C4948-S / WS-C4948-E-F-S) switch ports report "No Gbic" or "No X2"?

Asset ID:	1-72-1987045.1
Update Date:	2018-01-05
Keywords:

Solution Type Problem Resolution Sure

Solution 1987045.1 : Why do Cisco Catalyst 4948 (WS-C4948-S / WS-C4948-E-F-S) switch ports report "No Gbic" or "No X2"?

Applies to:

Exadata Database Machine X2-2 Hardware - Version All Versions and later
Exadata X3-2 Hardware - Version All Versions and later
Exadata X4-2 Hardware - Version All Versions and later
Information in this document applies to any platform.

Symptoms

On the Cisco Catalyst 4948 switches (WS-C4948-S) or the Cisco Catalyst 4948E-F switches (WS-C4948-E-F-S), at times, when customer runs "show interfaces status", some switch ports may report "No Gbic" or "No X2".

2 examples are given below.

>enable
#show interfaces status

Port      Name               Status       Vlan       Duplex Speed Type
...
Gi1/39                       connected    1          a-full a-1000 10/100/1000-TX
Gi1/40                       connected    1          a-full a-100 10/100/1000-TX
Gi1/41                       connected    1          a-full a-1000 10/100/1000-TX
Gi1/42                       connected    1          a-full a-100 10/100/1000-TX
Gi1/43                       connected    1          a-full a-1000 10/100/1000-TX
Gi1/44                       connected    1          a-full a-100 10/100/1000-TX
Gi1/45                       notconnect   1            full   1000 No Gbic
Gi1/46                       notconnect   1            full   1000 No Gbic
Gi1/47                       notconnect   1            full   1000 No Gbic
Gi1/48                       notconnect   1            full   1000 No Gbic

>enable
#show interfaces status

Port      Name               Status       Vlan       Duplex Speed Type
...
Te1/49       connected    trunk        full a-10G 10GBase-SR
Te1/50         connected    trunk        full a-10G 10GBase-SR
Te1/51     connected    trunk        full a-10G 10GBase-CU 5M
Te1/52                       notconnect   1            full   auto No X2

Why do Cisco Catalyst 4948 (WS-C4948-S / WS-C4948-E-F-S) switch ports report "No Gbic" or "No X2"?

Changes

Sometimes, this problem can be seen after an IOS firmware upgrade or after a reset (i.e. not just a reboot).

Another point to note is that the "no Gbic" issue is no longer appearing in newer IOS firmware versions, such as v15.x. The "no Gbic" issue is commonly seen in old er IOS firmware verions, such as v12.x.

Cause

The "No Gbic" message implies the switch port is actually expecting a Gbic to be inserted but none is actually present.

The Cisco Catalyst 4948 switch has 48 switch ports for normal UTP (TwinX or TX) connectors at speeds of 10/100/1000. However, sometimes, depending on the IOS firmware version, some switch ports may erronously expect Gbics to be present when cabled when in fact none is required.

The "No X2" message implies the switch port is actually expecting a transceiver to be inserted but none is actually present.

The Cisco Catalyst 4948E-F switch has additional 4 switch ports for SFP+ connectors at speeds of 10000. These switch ports naturally expect transceivers to be present when cabled.

Solution

To combat the "No Gbic" message, based on the above example, customer can do:

>enable
#show interfaces status
#show interface gi 1/45 capabilities
#show interface gi 1/46 capabilities
#show interface gi 1/47 capabilities
#show interface gi 1/48 capabilities

The switch port capabilities are expected to have something like:

Model:                 WS-C4948S-RJ-45
Type:                  10/100/1000-TX    <<-- expected
Speed:                 10,100,1000,auto
Duplex:                half,full,auto
Auto-MDIX:             yes

If the switch port capabilities are erronously expecting Gbics to be present when cabled, then customer can remedy this issue via:

>enable
#configure terminal
(config)#interface range gi 1/45 - 48
(config-if)#? <<-- to see what available commands are there
(config-if)#media-type rj45 <<-- to force media type to only expect an RJ45 connector
(config-if)#no shutdown
(config-if)#end
#show interfaces status

As for the "No X2" message, often it can simply mean the switch port is not cabled. However, if the switch port is indeed cabled, then customer will then need to verify the presence of 2 transceivers at both sides.

To see a list of Cisco supported transceivers and to force support for 3rd party transceivers, customer can do:

>enable
#show interfaces transceiver supported-list
#configure terminal
(config)#service unsupported-transceiver
(config)#end

If the above does not help, then replacing transceivers and cables becomes unavoidable.

References

<NOTE:1415044.1> - Upgrading firmware / Configuring SSH on Cisco Catalyst 4948 Ethernet Switch

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