6/13/23, 10:35 AM
`
`Re: [sipcore] Reuse of Sip Call-Id question..
`
`Re: [sipcore] Reuse of Sip Call-Id question..
`Paul Kyzivat <pkyzivat@cisco.com> Tue, 09 June 2009 13:08 UTCShow header
`
`Adam,
`
`I will agree with you on this one.
`
`Yet I want to emphasize the need for conservatism on the originating
`side. I have repeatedly seen cases where somebody says on of:
`- I can reuse the same callid because the from and to tags will
` make the dialog id unique
`- I can reuse the same from tag because the callid and to tag will
` make the dialog id unique
`- I can reuse the same to tag because the callid and from tag will
` make the dialog id unique
`
`Of course nobody agrees on which ones really must be unique.
`
`When you reason this way you are betting that everybody else involved
`has made compatible assumptions to the one you are making.
`
`Thanks,
`Paul
`
`Adam Roach wrote:
`> [as an individual]
`>
`> This is an excellent example of where Postel's Maxim would address the
`> problem. (For the unaware, Postel's Maxim is "be conservative in what
`> you do, be liberal in what you accept from others"). For the failure
`> Glenn is describing, it takes the efforts of two misbehaving systems to
`> cause a failure.
`>
`> There is nothing in RFC3261 that normatively assigns semantics to a
`> Call-ID by itself. It is meaningful only when combined with other
`> identifiers, such as To: and From: tags. If you have software that is
`> failing when it sees duplicate Call-IDs, then that is a bug that should
`> be resolved.
`
`https://mailarchive.ietf.org/arch/msg/sipcore/upW9qQwKWVxqxYMqPfEJ8gLdaZY/
`
`1/5
`
`ERICSSON EXHIBIT 1033
`Ericsson Inc. v. Koninklijke KPN N.V.
`IPR2022-00557, Page 1
`
`
`
`Re: [sipcore] Reuse of Sip Call-Id question..
`
`Re: [sipcore] Reuse of Sip Call-Id question..
`Paul Kyzivat <pkyzivat@cisco.com> Tue, 09 June 2009 13:08 UTCShow header
`
`Adam,
`
`I will agree with you on this one.
`
`Yet I want to emphasize the need for conservatism on the originating
`side. I have repeatedly seen cases where somebody says on of:
`- I can reuse the same callid because the from and to tags will
` make the dialog id unique
`- I can reuse the same from tag because the callid and to tag will
` make the dialog id unique
`- I can reuse the same to tag because the callid and from tag will
` make the dialog id unique
`
`Of course nobody agrees on which ones really must be unique.
`
`When you reason this way you are betting that everybody else involved
`has made compatible assumptions to the one you are making.
`
`Thanks,
`Paul
`
`Adam Roach wrote:
`> [as an individual]
`>
`> This is an excellent example of where Postel's Maxim would address the
`> problem. (For the unaware, Postel's Maxim is "be conservative in what
`> you do, be liberal in what you accept from others"). For the failure
`> Glenn is describing, it takes the efforts of two misbehaving systems to
`> cause a failure.
`>
`> There is nothing in RFC3261 that normatively assigns semantics to a
`> Call-ID by itself. It is meaningful only when combined with other
`> identifiers, such as To: and From: tags. If you have software that is
`> failing when it sees duplicate Call-IDs, then that is a bug that should
`> be resolved.
`
`https://mailarchive.ietf.org/arch/msg/sipcore/upW9qQwKWVxqxYMqPfEJ8gLdaZY/
`
`1/5
`
`ERICSSON EXHIBIT 1033
`Ericsson Inc. v. Koninklijke KPN N.V.
`IPR2022-00557, Page 1
`
`
`
`Re: [sipcore] Reuse of Sip Call-Id question..
`
`6/13/23, 10:35 AM
`>
`> However, this misbehavior wouldn't happen if the sending party were a
`> bit more conservative in what it sent -- if it were more vigorous in
`> generating new Call-IDs for new attempts.
`>
`> If we're seeing real-life failures due to this behavior, I'd say both
`> sides are at fault. It takes two to dance this "Failure Tango".
`>
`> /a
`>
`>
`> Hisham Khartabil wrote:
`>> The via branch is used to match transactions. The state machine doesnt
`>> care about call-id or tags when matching transactions (if it is
`>> RFC3261 compliant that is). So a question to Glenn. Is the branch also
`>> the same?
`>>
`>> The transaction layer will pass the request to the UAS Core if there
`>> is no match in the transaction (branch in top via header). In that
`>> case, the core will not find a dialog match (since it rejected the
`>> original request) and will process the new request as a new request.
`>>
`>> Hisham
`>>
`>> 2009/6/6 Dean Willis <dean.willis@softarmor.com>:
`>>
`>>> On Jun 5, 2009, at 10:18 AM, Cahall, Glenn wrote:
`>>>
`>>>
`>>>> Paul,
`>>>>
`>>>> Thanks for the response.
`>>>>
`>>>> Once I read your response, I felt that I needed to explain the
`>>>> situation
`>>>> in more detail.
`>>>>
`>>>> Customer is sending us an INVITE, our response is a 486 BUSY. This
`>>>> exact
`>>>> scenario (all with same TNs) repeats itself 100+ times over the next 90
`>>>> seconds or so. All 100+ INVITEs contain the same Call-Id. However,
`>>>> tag
`
`https://mailarchive.ietf.org/arch/msg/sipcore/upW9qQwKWVxqxYMqPfEJ8gLdaZY/
`
`2/5
`
`ERICSSON EXHIBIT 1033
`Ericsson Inc. v. Koninklijke KPN N.V.
`IPR2022-00557, Page 2
`
`
`
`Re: [sipcore] Reuse of Sip Call-Id question..
`
`6/13/23, 10:35 AM
`>>>> value in the From field is different.
`>>>>
`>>>> So....now that you know more about the situation....is this in
`>>>> violation
`>>>> of the RFC?
`>>>>
`>>>> Also, during our discussions on the topic, we argued whether or not
`>>>> Call-Id could be reused. In short, as stated before, even if the
`>>>> initial
`>>>> call was successful, they believed that as soon as that call was
`>>>> completed,
`>>>> they were free to use the exact same Call-Id on the very next call.
`>>>>
`>>>
`>>> The From: tag SHOULD be invariant if the Call-ID is re-used in
`>>> response to a
`>>> 4xx, else the transaction won't match. And the CSeq SHOULD increase,
`>>> since
`>>> it is a new INVITE. This is specified in paragraph 6 of section
`>>> 8.1.4.5 in
`>>> RFC 3261. In practice, state matching fails if this isn't honored, so it
`>>> really could have been specified as a MUST; that is, we should probably
`>>> rewrite RFC 3261 to say something like:
`>>>
`>>> "The UAC MAY retry a transaction following certain 400-class
`>>> responses, If
`>>> the UAC retries such a transaction, it MUST retain the To, From,
`>>> Call-ID and
`>>> Request-URI of the original transaction, and MUST increment the CSeq.
`>>> Failure to observe these two operational requirements is likely to
`>>> result in
`>>> proxies or the UAS not matching the retried transaction to any retained
`>>> state from previous transactions, which could result in errors
`>>> ranging from
`>>> erroneous log entries to denial-of-service scenarios, and it is in
`>>> extremely
`>>> poor taste too."
`>>>
`>>> In other words, the tag should be the same, the CSeq should
`>>> increment, and
`>>> you spank the customer for being annoying.
`>>>
`
`https://mailarchive.ietf.org/arch/msg/sipcore/upW9qQwKWVxqxYMqPfEJ8gLdaZY/
`
`3/5
`
`ERICSSON EXHIBIT 1033
`Ericsson Inc. v. Koninklijke KPN N.V.
`IPR2022-00557, Page 3
`
`
`
`Re: [sipcore] Reuse of Sip Call-Id question..
`6/13/23, 10:35 AM
`>>> Failing that, how's the Retry-After: header field on your 486 populated?
`>>> Perhaps you could crank it up to about 60 seconds, THEN spank them
`>>> for being
`>>> annoying it if they ignore it.
`>>>
`>>> --
`>>> Dean
`>>>
`>>>
`>>>
`>>> _______________________________________________
`>>> sipcore mailing list
`>>> sipcore@ietf.org
`>>> https://www.ietf.org/mailman/listinfo/sipcore
`>>>
`>>>
`>> _______________________________________________
`>> sipcore mailing list
`>> sipcore@ietf.org
`>> https://www.ietf.org/mailman/listinfo/sipcore
`>>
`>
`> _______________________________________________
`> sipcore mailing list
`> sipcore@ietf.org
`> https://www.ietf.org/mailman/listinfo/sipcore
`>
`
`[sipcore] Reuse of Sip Call-Id question.. Cahall, Glenn
`Re: [sipcore] Reuse of Sip Call-Id question.. Paul Kyzivat
`Re: [sipcore] Reuse of Sip Call-Id question.. Cahall, Glenn
`Re: [sipcore] Reuse of Sip Call-Id question.. Byron Campen
`Re: [sipcore] Reuse of Sip Call-Id question.. Paul Kyzivat
`Re: [sipcore] Reuse of Sip Call-Id question.. Attila Sipos
`Re: [sipcore] Reuse of Sip Call-Id question.. Attila Sipos
`Re: [sipcore] Reuse of Sip Call-Id question.. Byron Campen
`Re: [sipcore] Reuse of Sip Call-Id question.. Paul Kyzivat
`Re: [sipcore] Reuse of Sip Call-Id question.. Byron Campen
`Re: [sipcore] Reuse of Sip Call-Id question.. Cahall, Glenn
`Re: [sipcore] Reuse of Sip Call-Id question.. Dale Worley
`
`https://mailarchive.ietf.org/arch/msg/sipcore/upW9qQwKWVxqxYMqPfEJ8gLdaZY/
`
`4/5
`
`ERICSSON EXHIBIT 1033
`Ericsson Inc. v. Koninklijke KPN N.V.
`IPR2022-00557, Page 4
`
`
`
`6/13/23, 10:35 AM
`
`Re: [sipcore] Reuse of Sip Call-Id question..
`Re: [sipcore] Reuse of Sip Call-Id question.. Paul Kyzivat
`Re: [sipcore] Reuse of Sip Call-Id question.. Bob Penfield
`Re: [sipcore] Reuse of Sip Call-Id question.. Paul Kyzivat
`Re: [sipcore] Reuse of Sip Call-Id question.. Dean Willis
`Re: [sipcore] Reuse of Sip Call-Id question.. Dean Willis
`Re: [sipcore] Reuse of Sip Call-Id question.. Dale Worley
`Re: [sipcore] Reuse of Sip Call-Id question.. Dean Willis
`Re: [sipcore] Reuse of Sip Call-Id question.. Bob Penfield
`Re: [sipcore] Reuse of Sip Call-Id question.. Dale Worley
`Re: [sipcore] Reuse of Sip Call-Id question.. Hisham Khartabil
`Re: [sipcore] Reuse of Sip Call-Id question.. Adam Roach
`Re: [sipcore] Reuse of Sip Call-Id question.. Dean Willis
`Re: [sipcore] Reuse of Sip Call-Id question.. Paul Kyzivat
`Re: [sipcore] Reuse of Sip Call-Id question.. Dean Willis
`Re: [sipcore] Reuse of Sip Call-Id question.. Paul Kyzivat
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`https://mailarchive.ietf.org/arch/msg/sipcore/upW9qQwKWVxqxYMqPfEJ8gLdaZY/
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`5/5
`
`ERICSSON EXHIBIT 1033
`Ericsson Inc. v. Koninklijke KPN N.V.
`IPR2022-00557, Page 5
`
`
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