PPP synchronous and Asynchronous and clock rate

[zillah2004]

As we know that PPP used for synchronous and Asynchronous environment.

With synchronous we need to use clock rate, but we do not need to use it with Asynchronous.

Now If we encapsulate the serial interface (S0/0, S0/1) of a router with PPP, should we use clcok rate for that interface ?

[Georg Pauwen]

Hello,

when you configure the serial interface for async mode, you do not need the clock rate:

interface Serial0

physical-layer async

encapsulation ppp

In synchronous mode, you need the clock rate:

interface Serial0

encapsulation ppp

clock rate 125000

Is that what you are looking for ?

Regards,

GP

[zillah2004]

Thanks for that, yes this is what I was looking for.

Another question:

When can we use physical-layer async ? Is there any restrection for that?

As you know the Telcommunication infrastructure can be synch or asynch

[Georg Pauwen]

Hello,

AFAIK, asynchronous connections used to be only available on low-speed (<2MB) serial interfaces, but now, there are the new HWICs (High-Speed WAN Interface Cards) which also support async mode.

Check the link below for more info:

SERIAL AND ASYNCHRONOUS HIGH-SPEED WAN INTERFACE CARDS FOR CISCO 1800, 2800, AND 3800 SERIES INTEGRATED SERVICES ROUTERS

http://www.cisco.com/en/US/products/ps5949/products_qanda_item0900aecd80274424.shtml

HTH,

GP