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Bronze

relation between clock rate and port speed

Hi every body!

Say we have this set up r1s0---------dsu/csu------T1-----------------csu/dsu---r2

Dsu/csu say is using internal clock. what clock rate should be configured so that r1 can send data at 1.544 Mpbs.

To put it another way, How do we determine the clock rate for a port?

Thanks a lot!

2 ACCEPTED SOLUTIONS

Accepted Solutions
Hall of Fame Super Silver

Re: relation between clock rate and port speed

Hello Sarah,

the relationship is 1 to 1 in this case: the clock rate has to be set to 1544000 to allow the router to use a full T1 speed.

Edit:

there is the other thread where Victor, Edison and Vuyan have provided useful answers with a lot of detailed information you can find a better answer there

Hope to help

Giuseppe

Hall of Fame Super Bronze

Re: relation between clock rate and port speed

Sarah,

The clock rate command is used on DCE serial interfaces, not under internal CSU/DSUs.

Internal CSU/DSUs use the 'timeslot' concept:

http://www.cisco.com/en/US/docs/ios/interface/command/reference/ir_s2.html#wp1011734

If you purchased a T1, you will enable all timeslots in the CSU

service-module t1 timeslots 1-24, speed 64

HTH,

__

Edison.

4 REPLIES
Hall of Fame Super Silver

Re: relation between clock rate and port speed

Hello Sarah,

the relationship is 1 to 1 in this case: the clock rate has to be set to 1544000 to allow the router to use a full T1 speed.

Edit:

there is the other thread where Victor, Edison and Vuyan have provided useful answers with a lot of detailed information you can find a better answer there

Hope to help

Giuseppe

Bronze

Re: relation between clock rate and port speed

Thanks a lot Giuseppe and Edison !

Hall of Fame Super Bronze

Re: relation between clock rate and port speed

Sarah,

The clock rate command is used on DCE serial interfaces, not under internal CSU/DSUs.

Internal CSU/DSUs use the 'timeslot' concept:

http://www.cisco.com/en/US/docs/ios/interface/command/reference/ir_s2.html#wp1011734

If you purchased a T1, you will enable all timeslots in the CSU

service-module t1 timeslots 1-24, speed 64

HTH,

__

Edison.

Bronze

Re: relation between clock rate and port speed

Just one more question.

Please consider a frame relay network.

A router is connected to frame really network by s0. This router has point to point connection to other sides which are also connected to frame relay network.

Now does LMI messages are only exchanged on physical int i.e s0 or they are also exchanged on sub interfaces?

thanks a lot!

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