PPP Keepalive : LCP echo/request data length ?

[pascalfr0]

Hi,

We use PPP keepalive on PPP session between LNS (ASR1K) and CPE (cisco ISR G2, and some other vendors CPE routers).

If no reply is received after (i guess) 3 keepalive messages are sent on a ppp session, the ppp session goes down. Common practice.

The keepalive message are actually PPP LCP echo and PPP LCP request.

Is there a standard that set the length of the data in those keepalive messages ?

What is the default data length used by Cisco routers in LCP echo/request messages sent as PPP keepalive  ?

The answer is important for us in a very specific context.

[pascalfr0]

Answering my own question : ppp keepalives are 16 bytes ppp packets (4 bytes for ppp header + 12 bytes for lcp packet).

Don't know if this is a standard, but that's what I saw between ISR and ASR.
 

[acitycisco]

default is 10 seconds period, 5 keepalives sent