The IESG has approved the following document: - 'Pseudowire Congestion Considerations' (draft-ietf-pals-congcons-02.txt) as Informational RFC This document is the product of the Pseudowire And LDP-enabled Services Working Group. The IESG contact persons are Alvaro Retana, Alia Atlas and Deborah Brungard. A URL of this Internet Draft is: https://datatracker.ietf.org/doc/draft-ietf-pals-congcons/ Technical Summary Pseudowires (PWs) have become a common mechanism for tunneling traffic, and may be found in unmanaged scenarios competing for network resources both with other PWs and with non-PW traffic, such as TCP/IP flows. It is thus worthwhile specifying under what conditions such competition is acceptable, i.e., the PW traffic does not significantly harm other traffic or contribute more than it should to congestion. We conclude that PWs transporting responsive traffic behave as desired without the need for additional mechanisms. For inelastic PWs (such as TDM PWs) we derive a bound under which such PWs consume no more network capacity than a TCP flow. For TDM PWs, we find that the level of congestion at which the PW can no longer deliver acceptable TDM service is never significantly greater than this bound, and typically much lower. Therefore, as long as the PW is shut down when it can no longer deliver acceptable TDM service, it will never do significantly more harm than even a single TCP flow. We propose employing a transport circuit breaker to shut down a TDM PW that persistently fails to comply with acceptable TDM service criteria. Working Group Summary This draft was the result of one of the chartered work items in the PWE3 WG, "Publish document outlining PW-specific congestion avoidance and response guidelines." The process has been slow due to the challenge of finding a set of authors that were both qualified and willing to undertake the work in a thorough manner, and once they volunteered, competing demands for their time and changes in thei employment. The great majority of the work was done during the lifetime of the PWE3 WG. It received a good set of comments during WG LC, which have been included in the draft, and it is now ready for publication. Note that due to the use of modeling, simulations, and resulting color graphs, the PDF version of this draft is the canonical version. Document Quality This is informational, so there are no implementations. The draft received a thorough set of reviews from both WG chairs during WG LC, and I did another shepherd's review following WG LC comment resolution. Personnel Who is the Document Shepherd for this document? Who is the Responsible Area Director? If the document requires IANA experts(s), insert 'The IANA Expert(s) for the registries in this document are <TO BE ADDED BY THE AD>.' Andy Malis, Deborah Brungard