tcpdump mailing list archives
Re: Request for a new DLT for MTP2 with FCS
From: Florent.Drouin () alcatel-lucent fr
Date: Thu, 8 Feb 2007 19:44:12 +0100
I agree with you, the problem I am speaking about, seems to be a common problem. It is very difficult to differentiate a frame with FCS (Frame Check Sequence) and a frame without, if we are just looking at the linktype. But, with the current libpcap, I do not see other solutions, than using different linktypes. Is it really a problem to create new linktypes, just for such purpose ? (I understood that the linktypes are coded on 4 bytes ) Regards Florent Stephen Donnelly <stephen () endace com> To: tcpdump-workers () lists tcpdump org Sent by: cc: tcpdump-workers-owner@lists. Subject: Re: [tcpdump-workers] Request for a new DLT for MTP2 with FCS tcpdump.org 07/02/2007 05:37 Please respond to tcpdump-workers On Tue, 2007-02-06 at 18:18 +0100, Florent.Drouin () alcatel-lucent fr wrote:
Hello,
I need a new datalink value (LINKTYPE_MTP2_FCS) to manage MTP2 frame with Checksum. (See http://www.wireshark.org/lists/wireshark-dev/200702/msg00206.html ) Once I will have the value, I will provide the patch for libpcap.
Endace DAG cards (for instance) can capture MTP2 with or without FCS, does your proposal mean that MTP2 without FCS should only use LINKTYPE_MTP2 and MTP2 with FCS should only use LINKTYPE_MTP2_FCS? What about other linktypes, such as Ethernet? The issue of whether captured packets should include FCS and how this is reported in libpcap seems to be a more generic question. I'm not sure that duplicating all existing DLTs by adding _FCS (or tripling with _NOFCS as well) at the end would be accepted by the libpcap community. If people are generally happy with adding LINKTYPE_MTP2_FCS as a special case I have no problem, and Endace can support both linktypes. Stephen. -- ----------------------------------------------------------------------- Stephen Donnelly BCMS PhD email: sfd () endace com Endace Technology Ltd phone: +64 7 839 0540 Hamilton, New Zealand cell: +64 21 1104378 ----------------------------------------------------------------------- - This is the tcpdump-workers list. Visit https://cod.sandelman.ca/ to unsubscribe. - This is the tcpdump-workers list. Visit https://cod.sandelman.ca/ to unsubscribe.
Current thread:
- Request for a new DLT for MTP2 with FCS Florent . Drouin (Feb 06)
- Re: Request for a new DLT for MTP2 with FCS Stephen Donnelly (Feb 06)
- Re: Request for a new DLT for MTP2 with FCS Florent . Drouin (Feb 08)
- Re: Request for a new DLT for MTP2 with FCS Stephen Donnelly (Feb 08)
- Re: Request for a new DLT for MTP2 with FCS Guy Harris (Feb 08)
- Re: Request for a new DLT for MTP2 with FCS Florent . Drouin (Feb 08)
- Re: Request for a new DLT for MTP2 with FCS Stephen Donnelly (Feb 06)