Wireshark mailing list archives
Re: HP ERM
From: Gene Cumm <gene.cumm () gmail com>
Date: Mon, 20 Feb 2017 08:52:48 -0500
On Mon, Feb 20, 2017 at 8:11 AM, Alexis La Goutte <alexis.lagoutte () gmail com> wrote:
Hi Gene, On Mon, Feb 20, 2017 at 2:05 PM, Gene Cumm <gene.cumm () gmail com> wrote:First, thanks for WireShark and granting my access request.Welcome :-)Second, I've found out more about the HP ERM format. The most significant bit of hp_erm.unknown3 indicates if the frame was untagged (0) or tagged (1). I'm writing a patch for review now.Ok nice !Would hp_erm.tag, hp_erm.tagged, or some other name seem the more appropriate name for such a value?Do you have found some spec or from feature on switchs ? if it is a "flag", the display filter hp_erm.is_tagged can be a idea...
Nope, no specification found, unfortunately. Just observation of known port states and happening to notice that value changed. See also the samples I uploaded over the weekend. The only combination I can think of that I didn't check is if a frame is 802.1q tagged with VLAN ID 0 in order to apply a non-default priority. Thanks for the suggestion to rename it. I do however suspect hp_erm.unknown1 might have been allocated for a timestamp like NTP's 64-bit timestamp but has never been implemented. I've recently hit a situation where packet captures required perfect in-order mirroring/tapping as none of the PXE clients I have feature an IP stack that can deal with out of order IP fragment delivery except through retries. If HP had added timestamps there, they could have been used to resequence frames from an ERM rather than needing on-site access to verify status. -- -Gene ___________________________________________________________________________ Sent via: Wireshark-dev mailing list <wireshark-dev () wireshark org> Archives: https://www.wireshark.org/lists/wireshark-dev Unsubscribe: https://www.wireshark.org/mailman/options/wireshark-dev mailto:wireshark-dev-request () wireshark org?subject=unsubscribe
Current thread:
- HP ERM Gene Cumm (Feb 20)
- Re: HP ERM Alexis La Goutte (Feb 20)
- Re: HP ERM Gene Cumm (Feb 20)
- Re: HP ERM Alexis La Goutte (Feb 20)