Duplex Mismatch between Cisco 2960 (LANBase Image) and Cisco 6506 Switch

edwardwaithaka · ‎01-22-2010

Hi,

I have the following issue;

I am getting a duplex mismatch between a Cisco 2960 TT-L Switch running IOS 12.2(35) LAN Base Image (Gig0/1) and a Cisco 6506 Switch running IOS 12.2(33)SXH Adv IP Services (Gig2/19).

I have tried several combinations of the duplex/speed settings on both sides but the only that works is setting duplex/speed AUTO on the Cisco 2960 which ends up autonegotiating to HALF duplex and 100Mbps.

What cou;d be the issue? IOS bugs?

Regards,

Edd.

arianto.wibowo · ‎01-22-2010

is it using UTP cable ?

please try to replace with another cable.

edwardwaithaka · ‎01-22-2010

Hi,

I have upgraded the Cisco 2960 Switch to version 12.2(52). The interfaces are now at FULL duplex but cannot negotiate to 1000Mbps.

zvondovec · ‎01-22-2010

Hi,

Can you put here results of sh run int ... commands?

thnx

edwardwaithaka · ‎01-22-2010

Hi,

Ports are on default;

2960

-------

int gig0/1

switchport mode access

switchport access vlan zzz

duplex auto

speed auto

6500

--------

int gig2/18

no switchport

ip address x.x.x.x y.y.y.y

no speed

no duplex

zvondovec · ‎01-22-2010

Hi,

Is there only cable between those 2 boxes, or is there some convertor (fiber optic)?

Also you can try speed nonegotiate command on both sides.

bye

vvasisth · ‎01-22-2010

i am pretty sure i saw a similar bug.

Varun

Leo Laohoo · ‎01-22-2010

On both, try the following interface command "speed auto 1000".

glen.grant · ‎01-23-2010

It is generally advised you use auto on both sides for gigabit. If they are not negotiating gig then I would take a serious look at the cabling . Unlike fastether which takes 2 pairs you must have 8 good wires in the entire path between the 2 devices in order to negotiate gig as gig uses all 8 wires to achieve gig speeds . Even 1 bad wire out of the 8 it will not negotiate gig . Make sure speed negotation is actually turned on for the 6500. you can check this with the following counterintuitive command

no speed nonegotiate .  Verify with the command show interfaces GigabitEthernet slot/port transceiver properties

Good info for explaining the different states for gig port settings. http://www.cisco.com/en/US/docs/switches/lan/catalyst6500/ios/12.2SX/configuration/guide/intrface.html#wp1020621

jimenez.reuben · ‎06-28-2012

On the 2960 switch the "dual purpose" uplinks need to be manually configured with "media-type" to be able to set speed/duplex. Default would not allow setting these 2 attributes.

interface GigabitEthernet0/1

switchport mode trunk

media-type rj45

speed 100

duplex full

end

GigabitEthernet0/1 is down, line protocol is down (notconnect)

Hardware is Gigabit Ethernet, address is

Description: Uplink to Cat01

MTU 1500 bytes, BW 10000 Kbit, DLY 1000 usec,

reliability 255/255, txload 1/255, rxload 1/255

Encapsulation ARPA, loopback not set

Keepalive not set

Full-duplex, 100Mb/s, link type is auto, media type is 10/100/1000BaseTX

http://www.cisco.com/en/US/docs/switches/lan/catalyst2960/software/release/12.2_55_se/configuration/guide/swint.html#wp2219831