HDLC Layer 2 Address

[Ahmed Mukhtar]

Hi,

   Although i teach CCNA and CCNP and i still dont understand the concept of HDLC...

i know that Ethernet uses MAC addresses at layer 2, Frame Relay uses DLCI numbers at layer 2 ok great....Then what does HDLC use????

Dosent HDLC has a layer 2 address too? like FR or Ethernet??

Please do clarify me in simple words

Thank You

[Richard Burts]

In simple words - HDLC does not use a layer 2 address to identify devices on the connection. HDLC does not need a layer 2 address in the same way that Ethernet or Frame Relay do. With Ethernet and Frame Relay there can be multiple remote devices connected on the media and you need a layer 2 address to uniquely identify each device. With HDLC it is a point to point connection and there is never more than one other device connected and no layer 2 address is required.

HTH

Rick

[Ahmed Mukhtar]

Thanks Richard Nice explanation...

but still iam a litlle bit confused....can u give me a link which can explain all this...

And Do tell me about SLARP which is used in HDLC

Thank You

[Richard Burts]

Here is a link that talks about Cisco HDLC and about SLARP. I hope that you find it useful.

HTH

Rick