4900M with 2x WS-X4908-10G-RJ45 half card - connecting to 1Gb switch

[leoruben2308]

Hi there,

I was hoping someone could please answer something for me as I see someone else had the same query a while back here and it looks like he found the answer himself but it was not confirmed;

https://supportforums.cisco.com/thread/2157239

I want to be able to connect a standard 1Gb Cisco switch to one of the 10G-Base-t ports on the 4900M (uses 2

WS-X4908-10G-RJ45 half cards), and also connect a Cisco ASA 5510 which only has 1Gb ports too to one of the 10GB ports... the rest of the 10GB ports are goingto be used to connect to 10GB NIC's on servers.

I see on that discussion it was stated;

And by the way it is possible

the command is

hw-module module 2 port-group 1 select gigabitethernet

this sets port 2/1 and port 2/2 to gig

they are both set due to the way the ASIC in the card works

yes it works

Does this work? Can we confirm it is possible?

Thanks.

[Aninda Chatterjee]

Hi Leo,

The 4900M has 8 fixed 10G ports and two half card slots which can be used to install a 10G X2 half card (which is twingig module compatible).

The 8 fixed 10G ports will only operate at 10G and cannot be changed. However, you can use this half card to further install a TwinGig converter which converts a 10G port into two gig ports.

The command for this, as stated by you, is hw-module module port-group select [tengig|gig]

You can verify the port-group mapping for that module using the show hw-module module port-group command.

Hope this helps.

- Aninda

[leoruben2308]

Hi Aninda,

Thanks but this is not the answer im looking for. We already have the 4900M and two WS-X4908-10G-RJ45 half cards which are populating the two half card slots (we arent using any 10G X2 half cards)

We need the switch to have 2 of these half cards (WS-X4908-10G-RJ45) as we need more than 8 10G-Base-T ports (this provides 16). However we want to make a couple of the ports on one of the half cards 1Gb Base-T (RJ45) to be able to connect the another switch which only has 1GB RJ45 uplinks.

Going by the Cisco data sheet on the 4900M, it should be possible but I can not find any other info anywhere about how this is configured...

Figure 5.

8-Port (2:1) 10GBASE-T RJ-45 Half Card

¹

(Capable of Operating at 1G/10G for Up to 100m on Cat6a/Cat7 Cable)

http://www.cisco.com/en/US/prod/collateral/switches/ps5718/ps6021/ps9310/Data_Sheet_Cat_4900M.html

[Giuseppe Larosa]

Hello Leo,

if you have already the hardware you should be able to quickly test the proposed solution to make two ports to run at 1Gbps connect one port to a 1Gbps device and try to configure the command for hardware selection and see if you are able to have link up/up and put some test traffic on it.

All I can say is that this is the same command used to make the 4900M to recognize twingig transceivers and to use SFP optics installed on the twingig. I have used twingig successfully.

It makes sense that Cisco reused the same command syntax for the 10 G RJ45 half card.

I encourage you to post the test results.

Edit:

in the case of your linecard it may be even auto-sense so you should first try to connect a 1Gbps device without adding any command.

Hope to help

Giuseppe

[Ivan Shirshin · Accepted solution]

Hello Leo,

The 10GBASE-T line-card module on the Cisco Catalyst 4900M supports  Gigabit Ethernet or 10 Gigabit Ethernet mode for each port group. The

eight ports are divided into four port groups, and each port group can be configured to operate in either Gigabit Ethernet or 10 Gigabit

Ethernet mode. All ports within the same port group must have the same mode.

The ports cannot auto negotiate to Gigabit speeds, that is why it shows TenGigabit ports or Gigabit ports.

You can see in the config and outputs 8 TenG and 8 Gb ports, e.g. below:

interface TenGigabitEthernet2/1 ! interface TenGigabitEthernet2/2 ! interface TenGigabitEthernet2/3 ! interface TenGigabitEthernet2/4 ! interface TenGigabitEthernet2/5 ! interface TenGigabitEthernet2/6 ! interface TenGigabitEthernet2/7 ! interface TenGigabitEthernet2/8 ! interface GigabitEthernet2/9 ! interface GigabitEthernet2/10 ! interface GigabitEthernet2/11 ! interface GigabitEthernet2/12 ! interface GigabitEthernet2/13 ! interface GigabitEthernet2/14 ! interface GigabitEthernet2/15 ! interface GigabitEthernet2/16

And you can check the current settting for each port group below:

Switch#sho hw-module module 3 port-group

Module Port-group Active                         Inactive

-------------------------------------------------------------

   2        1     Te2/1-2                        Gi2/9-10

   2        2     Te2/3-4                        Gi2/11-12

   2        3     Te2/5-6                        Gi2/13-14

   2        4     Te2/7-8                        Gi2/15-16

The command to change between TenG and Gb modes is "hw-module module 2 port-group 1 select gigabitethernet", as you mentioned in the beginning.

Also, I see you mentioned thst you cannot find information on 4900m configuration. 4900 and 4500 share the same configuration guides. Check here for the one matching your SE release:

http://www.cisco.com/en/US/products/ps6021/products_installation_and_configuration_guides_list.html

Kind Regards,

Ivan Shirshin

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[sumit mehta]

Hello

I have a question regarding this may be a stupid one :) .

Can we use both 10g ports in a port group as 10g ports or is it like if we use one we cannot use the other one.

3        1     Te3/1-2

for example in the above line can we use both ports te3/1 and te3/2 as separate 10g ports ?