This is the second time I have seen a post about HDLC enabling the router to
retransmit, and some other people who I have brought the topic up to seem to
think so to, so I dug up what Cisco says about HDLC encapsulation.
"HDLC Serial Encapsulation Method
Cisco provides HDLC serial encapsulation for serial lines. This
encapsulation method provides the synchronous framing and error detection
functions of HDLC without windowing or retransmission."
Note: without retransmission
http://www.cisco.com/univercd/cc/td/doc/product/software/ssr83/rpc_r/61110.h
tm
-----Original Message-----
From: Jeremy Dumoit [mailto:[EMAIL PROTECTED]]
Sent: Thursday, February 08, 2001 5:10 PM
To: Leigh Anne Chisholm; [EMAIL PROTECTED]
Subject: RE: not quite sure...
Frame relay has no means for packet loss
detection, so a higher layer protocol (probably TCP)
would have to request retransmission of the data.
This would occur between hosts rather than the router.
X.25 and HDLC on the other hand are both reliable
protocols... they would recognize a packet loss and
retransmit from the routers. However, PPP, like
frame, is just a datagram service... the hosts would
have to work it out at higher layers again.
--- Leigh Anne Chisholm <[EMAIL PROTECTED]> wrote:
> Would Router B retransmit if Frame Relay was used as
> the encapsulation
> protocol? If so, how would Frame Relay detect the
> loss of the "packet"?
> What about X.25--would Router B retransmit? How
> would X.25 detect the loss?
> What about HDLC? PPP?
>
> -----Original Message-----
> From: [EMAIL PROTECTED]
> [mailto:[EMAIL PROTECTED]]On Behalf Of
> Brant Stevens
> Sent: February 8, 2001 9:10 AM
> To: Dennis Laganiere; [EMAIL PROTECTED]
> Subject: RE: not quite sure...
>
>
> The question is if Router B and Router C are
> routing, or if they are
> bridging... If they are routing, then Router B
> would re-transmit a packet.
> If bridging is happening, then Host A would
> retransmit...
>
> Hope this helps...
>
> Brant I. Stevens
> Internetwork Solutions Engineer
> Thrupoint, Inc.
> 545 Fifth Avenue, 14th Floor
> New York, NY. 10017
> 646-562-6540
>
> -----Original Message-----
> From: [EMAIL PROTECTED]
> [mailto:[EMAIL PROTECTED]]On Behalf Of
> Dennis Laganiere
> Sent: Wednesday, February 07, 2001 11:32 PM
> To: '[EMAIL PROTECTED]'
> Subject: not quite sure...
>
>
> I've tried to diagram this question to make it
> clear...
>
> Host A is sending to Host D...
>
> A line error occurs on the serial link between
> Router-B and Router-C while
> passing a packet from Host-A to Host-B
>
> Devices - Host A---------ROUTER B---------ROUTER
> C--------HOST D
> Interfaces - (A1) (B1) (B2) (C1)
> (C2) (D1)
>
> What device would rebroadcast?
>
> I think that router-B (port B2) would realize an
> error had occured, and
> would resend, so the answer should be port B2, but
> I've been through all my
> books and can't find anything to confirm or deny my
> conclusion...
>
> Any thoughts?
>
> _________________________________
> FAQ, list archives, and subscription info:
> http://www.groupstudy.com/list/cisco.html
> Report misconduct and Nondisclosure violations to
> [EMAIL PROTECTED]
>
> _________________________________
> FAQ, list archives, and subscription info:
> http://www.groupstudy.com/list/cisco.html
> Report misconduct and Nondisclosure violations to
> [EMAIL PROTECTED]
>
> _________________________________
> FAQ, list archives, and subscription info:
> http://www.groupstudy.com/list/cisco.html
> Report misconduct and Nondisclosure violations to
[EMAIL PROTECTED]
__________________________________________________
Do You Yahoo!?
Get personalized email addresses from Yahoo! Mail - only $35
a year! http://personal.mail.yahoo.com/
_________________________________
FAQ, list archives, and subscription info:
http://www.groupstudy.com/list/cisco.html
Report misconduct and Nondisclosure violations to [EMAIL PROTECTED]
_________________________________
FAQ, list archives, and subscription info: http://www.groupstudy.com/list/cisco.html
Report misconduct and Nondisclosure violations to [EMAIL PROTECTED]
