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

Welcome to Cisco Support Community. We would love to have your feedback.

For an introduction to the new site, click here. If you'd prefer to explore, try our test area to get started. And see here for current known issues.

New Member

Ques about interface Bandwidth

Hi Experts,

I have always had this ques in my mind and wanted to clarify...When we do a show interface on a router for a V.35 serial interface, the interface bandwidth shows as 1544 Kbps...is it because these routers are manufactured in the US and are set to default T1 BW or is it so that these interfaces cannot support line speeds of more than 1.544 Mbps. Would appreciate if someone can please clarify the same.

Many thanks in advance.

  • WAN Routing and Switching
1 ACCEPTED SOLUTION

Accepted Solutions

Re: Ques about interface Bandwidth

Hi,

The default bandwidth for WIC serial interfaces is 1544kbps as shown in the output of show interface but it can have up to 2.048 Mbps physical speed, but the bandwidth parameter itself can be <1-10000000> kilobits, which as i said doesn't reflect the physical speed in any means.

HTH,

Mohammed Mahmoud.

14 REPLIES

Re: Ques about interface Bandwidth

Hi,

This is the default value, and please keep in mind that this value doesn't reflect or control the actual speed of the interface this value is used by the IOS features (QoS, routing protocols, ...) and can be changed.

Router(config-if)#bandwidth ?

<1-10000000> Bandwidth in kilobits

HTH,

Mohammed Mahmoud.

Hall of Fame Super Bronze

Re: Ques about interface Bandwidth

The bandwidth value on a interface is inherited from the type of card in the slot. If you look at the model of the card, perhaps it's a T1 card not an E1 card. If you were to insert a DS3 card, the interface bandwidth value would be 45Mbps

Re: Ques about interface Bandwidth

Hi,

The default bandwidth for WIC serial interfaces is 1544kbps as shown in the output of show interface but it can have up to 2.048 Mbps physical speed, but the bandwidth parameter itself can be <1-10000000> kilobits, which as i said doesn't reflect the physical speed in any means.

HTH,

Mohammed Mahmoud.

Hall of Fame Super Bronze

Re: Ques about interface Bandwidth

I haven't had the pleasure to deal with E1 circuits, but since you do, what's the part number of the card that connects to this type of circuit ?

I never claimed that's the maximum speed, I explained how this default value is derived.

Hall of Fame Super Gold

Re: Ques about interface Bandwidth

Edison, there are many, nowadays the most used are VWIC-xMFT-E1 and VWIC2-xMFT-T1/E1 for the small and medium routers.

Hall of Fame Super Bronze

Re: Ques about interface Bandwidth

Thanks Paolo, I was trying to find in the Cisco website and couldn't find a part number hence my query.

What's the default BW for this type of card ?

It can't be 1544Kbps, can it ?

Hall of Fame Super Gold

Re: Ques about interface Bandwidth

It depends on how many timeslots are configured for the channel-group. IOS multiplies that by 64 and result is the default bandwidth. Same logic as for T1 channelized interfaces.

Hall of Fame Super Bronze

Re: Ques about interface Bandwidth

If you have an E1 with all timeslots (32), the interface will have a BW value of 2048kbps ?

If that's the case, then the OP was looking at a WIC1T serial card which is for T1 circuits (mostly American circuits) or a E1 serial card with 24 timeslots configured.

Re: Ques about interface Bandwidth

Hi Edison,

I think the original poster is talking about a WIC-1T (or maybe also a WIC-2T - it doesn't matter), although the default bandwidth under these interfaces is 1544 (which we all agree that it doesn't reflect the physical speed) but these interfaces can take physically upto E1 speed.

HTH,

Mohammed Mahmoud.

336
Views
19
Helpful
14
Replies