Cisco Support Community
cancel
Showing results for 
Search instead for 
Did you mean: 
Community Member

HWIC-1T port speed

Hello guys,

I have two questions.

I recently purchesed quite a few number of HWIC-1T cards. In the Cisco website, it stated that it can support upto 8Mbps speed. But when i connect to the Router, the speed is showing as 1544Kbps. Why is this? How can i acheive 8Mbps?

The second question is, I have few HWIC-4T card also. Cisco documents says, it can support Mbps per port. Where as the Cisco router shows the speed as 2Mbps. How can i acheive 8Mbps?

If i change bandwidth using 2bandwidth 8000" command, will that do the job?

Regards

Nimalraj

1 ACCEPTED SOLUTION

Accepted Solutions
Cisco Employee

Re: HWIC-1T port speed

Hello Nimalraj,

You are correct - the router interface is operating in the DTE mode and adapts itself to the clocking provided by the opposite device. In this case, you cannot control the clockrate yourself. You are literally at the "mercy" of the DCE device.

Best regards,

Peter

6 REPLIES
Cisco Employee

Re: HWIC-1T port speed

Nimalraj,

The "speed" you are referring to is probably the bandwidth operational parameter of an interface. This does not have anything to do with the real transmission speed of a serial interface and must be manually configured to match the true speed.

On serial interface, the transmission speed can be configured using the clock rate command provided that the HWIC card is the DCE device. In most router-to-modem scenario, this is not the case as the router performs as a DTE device (among other things, it adapts to the clocking signal from the modem and it does not assert its own clocking on the line) while the modem, as a DCE device, provides the clocking. However, when connecting two routers back-to-back using a DCE/DTE serial cable, one of the routers will also provide the clocking of the serial link. The clock rate is given in bits per seconds (actually in Hertz but a single tick of clock allows each router to send a single bit of data, thus the clock rate directly translates to bps). If you want to achieve the 8 Mbps on your HWIC card then you should configure your interface using the command clock rate 8000000.

Please note that the maximal speed of the serial interface depends also on the actual router hardware. With older routers like 2600 series, the maximal supported speed is 4 Mbps although the HWIC card itself is capable of speeds up to 8 Mbps. In recent ISR series (x800, x900), this should not be an issue anymore.

Best regards,

Peter

Community Member

Re: HWIC-1T port speed

Hello Peter, you answer was relly brief. Thanks for that.

In my scenario, I am connecting the 2811 Router to a Modem using a serial cable. I think, the DTE/DCE depends on the serial cable which I use. How can I know which side is DTE and which side is DCE? Is it is possible to know from the Router show commands?

Nimalraj

Cisco Employee

Re: HWIC-1T port speed

Hello Nimalraj,

The DTE/DCE indeed depends on the cable type but a modem would be connected to a router with a single V.35 or X.21 cable and the type would be strictly imposed by the modem (the polarity of the V.35/X.21 connector on the modem (male/female) would directly result in an appropriate cable type (DCE/DTE) being used for this interconnection).

Sometimes, the cables are labeled, like V.35MT (Male, DTE) or V.35FC (Female, DCE). And of course, it is possible to see the cable type on the router - use the command show controllers serial 0/0/0 and watch carefully - on the first page somewhere in the first 5-10 lines, the type of the cable will be indicated. Be sure to connect the cable and activate the interface beforehand.

Best regards,

Peter

Community Member

Re: HWIC-1T port speed

Peter, This is the output of the show controllers command with the cable ON.

Router#sh controllers s0/0/0
Interface Serial0/0/0
Hardware is GT96K
DTE 530idb at 0x43E82694, driver data structure at 0x43E89DA0
wic_info 0x43E8A3CC
<>>.

Also, when i tried to configure the clock rate, I got the following message.

,

Router(config)#int s0/0/0
Router(config-if)#clock rate
Router(config-if)#clock rate 4000000
This command applies only to DCE interfaces
Router(config-if)#

Does both the output suggests, I have DTE at Router side?

Nimalraj

Cisco Employee

Re: HWIC-1T port speed

Hello Nimalraj,

You are correct - the router interface is operating in the DTE mode and adapts itself to the clocking provided by the opposite device. In this case, you cannot control the clockrate yourself. You are literally at the "mercy" of the DCE device.

Best regards,

Peter

Community Member

Re: HWIC-1T port speed

Hello Peter, Thanks alot for your time and help. I really appreciate it.

Nimalraj

2904
Views
0
Helpful
6
Replies
CreatePlease to create content