Solved: HDLC encapsulation

mailaglady2 · ‎03-26-2009

I am running ios 12.4(20)T and my problem is when i configured HDLC, my connectivity drops intermittently but when I use frame-relay or PPP it functions normally. Can somebody confirm this for me, has any of you encountered this problem OR running HDLC without problems?

paolo bevilacqua · ‎03-27-2009

It's strange that you have a clock-rate configured. Likely you have an errored circuit, post output of show interface serail 0/3/0

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lamav · ‎03-26-2009

Cisco routers use a proprietary extension to the industry-standard HDLC frame. It's called cHDLC and it utilizes a "network protocol" field in the header to support several different higher layer protocols that HDLC will encapsulate.

If you're peering with a non-Cisco router and using HDLC encapsulation, you may have a problem.

If they are both Cisco, you should not, in which case you may post your interface and CSU/DSU configurations here for us to examine.

If they are both non-Cisco, make sure that they both use the same HDLC implementation.

HTH

Victor

mailaglady2 · ‎03-27-2009

there's not a lot of configs, and the other side they exactly the same with different ip's.

!

interface GigabitEthernet0/0

ip address 192.4.1.1 255.255.255.0

duplex auto

speed auto

media-type rj45

!

interface Serial0/3/0

ip address 165.148.120.1 255.255.255.252

clock rate 2000000

paolo bevilacqua · ‎03-27-2009

It's strange that you have a clock-rate configured. Likely you have an errored circuit, post output of show interface serail 0/3/0

mailaglady2 · ‎03-27-2009

The strange thing is I am not getting that problem no more, everything is working fine now. I have configured clock rate because i am using traffic generator and I find it more accurate with clock rate configured than bandwidth command.. Thanks for all the help.

paolo bevilacqua · ‎03-27-2009

When you connect two router back-to-back with serial interface, the DCE side always have clock-rate commands.