# NewSeqNo usage on SequenceReset-GapFill

**URL:** <https://forum.fixtrading.org/t/newseqno-usage-on-sequencereset-gapfill/3050>\
**Category:** General Q&A\
**Tags:** general-qa, xid\_166525, imported\
**Created:** [November 22, 2002, 5:06pm UTC](https://forum.fixtrading.org/t/newseqno-usage-on-sequencereset-gapfill/3050 "2002-11-22T17:06:00Z")\
**Posts on this page:** 4\
**Page:** 1

<div class="post-metadata">

**Author:** ![timolson59\_x](https://avatars.discourse-cdn.com/v4/letter/t/f0a364/32.png) [@timolson59\_x](https://forum.fixtrading.org/u/timolson59_x)\
**Post date:** [November 22, 2002, 5:06pm UTC](https://forum.fixtrading.org/t/newseqno-usage-on-sequencereset-gapfill/3050/1 "2002-11-22T17:06:00Z")

</div>

Imported from previous forum

---

<div class="post-metadata">

**Author:** ![timolson59\_x](https://avatars.discourse-cdn.com/v4/letter/t/f0a364/32.png) [@timolson59\_x](https://forum.fixtrading.org/u/timolson59_x)\
**Post date:** [November 22, 2002, 5:06pm UTC](https://forum.fixtrading.org/t/newseqno-usage-on-sequencereset-gapfill/3050/2 "2002-11-22T17:06:00Z")

</div>

Please excuse what is probably a remedial  
question, but I’m having trouble interpreting  
the 4.2 specification in regards to  
SequenceReset-GapFill.

"The message in all situations specifies NewSeqNo  
to reset as the value of the next sequence number  
immediately following the messages and/or  
sequence numbers being skipped"  
-FIX4.2 Spec (with errata 20010501)

Say I’ve already sent messages 1-100.

When responding to a resend request for messages  
50-75 (assuming 50-75 are administrative) do I  
send a GapFill with:

A. MsgSeqNum=50 NewSeqNo=76

or

B. MsgSeqNum=50 NewSeqNo=101

I think "A" because 76 is the next sequence number  
immediately following the messages being skipped  
(50-75).

I have a vender which is expecting "B" and I was wondering if this breaks the protocol.

Any input is appreciated. Thanks.

Thanks.

* * *

Tim A. Olson  
[tolson@manfinancial.com](mailto:tolson@manfinancial.com)

---

<div class="post-metadata">

**Author:** ![amitwamburkar23\_x](https://avatars.discourse-cdn.com/v4/letter/a/ecb155/32.png) [@amitwamburkar23\_x](https://forum.fixtrading.org/u/amitwamburkar23_x)\
**Post date:** [November 22, 2002, 5:42pm UTC](https://forum.fixtrading.org/t/newseqno-usage-on-sequencereset-gapfill/3050/3 "2002-11-22T17:42:00Z")

</div>

It depends upon whether messages from 76 to 100 are to be sent or not.  
If you do not want to send them, set NewSeqNo to 101.  
or  
set NewSeqNo to 76, resend messages from 76 to 100.

i guess what you shouldn’t do is set it to 76 and then send next message at seqNo 101.  
i hope i am not entirely wrong.  
\>  
\> Please excuse what is probably a remedial  
\> question, but I’m having trouble interpreting  
\> the 4.2 specification in regards to  
\> SequenceReset-GapFill.  
\>  
\>  
\> “The message in all situations specifies NewSeqNo  
\> to reset as the value of the next sequence number  
\> immediately following the messages and/or  
\> sequence numbers being skipped”  
\> -FIX4.2 Spec (with errata 20010501)  
\>  
\>  
\> Say I’ve already sent messages 1-100.  
\>  
\> When responding to a resend request for messages  
\> 50-75 (assuming 50-75 are administrative) do I  
\> send a GapFill with:  
\>  
\> A. MsgSeqNum=50 NewSeqNo=76  
\>  
\> or  
\>  
\> B. MsgSeqNum=50 NewSeqNo=101  
\>  
\>  
\>  
\> I think “A” because 76 is the next sequence number  
\> immediately following the messages being skipped  
\> (50-75).  
\>  
\> I have a vender which is expecting “B” and I was wondering if this breaks the protocol.  
\>  
\> Any input is appreciated. Thanks.  
\>  
\> Thanks.  
\>  
\> -------------------------------------------------  
\> Tim A. Olson  
\> [tolson@manfinancial.com](mailto:tolson@manfinancial.com)  
\>  
\>

---

<div class="post-metadata">

**Author:** ![timolson59\_x](https://avatars.discourse-cdn.com/v4/letter/t/f0a364/32.png) [@timolson59\_x](https://forum.fixtrading.org/u/timolson59_x)\
**Post date:** [November 22, 2002, 6:01pm UTC](https://forum.fixtrading.org/t/newseqno-usage-on-sequencereset-gapfill/3050/4 "2002-11-22T18:01:00Z")

</div>

That’s why I’m confused. The GapFill should just be filling in messages 50-75 because that is what  
the server was asking for. Why would I resend  
50-100 if the server asked for 50-75? If the  
server asked for 50-0 (inifinity) then, of course, I’d send 101 as NewSeqNo. (assuming  
75-100 were administrative)

\> It depends upon whether messages from 76 to 100 are to be sent or not.  
\> If you do not want to send them, set NewSeqNo to 101.  
\> or  
\> set NewSeqNo to 76, resend messages from 76 to 100.  
\>  
\> i guess what you shouldn’t do is set it to 76 and then send next message at seqNo 101.  
\> i hope i am not entirely wrong.  
\> \>  
\> \> Please excuse what is probably a remedial  
\> \> question, but I’m having trouble interpreting  
\> \> the 4.2 specification in regards to  
\> \> SequenceReset-GapFill.  
\> \>  
\> \>  
\> \> “The message in all situations specifies NewSeqNo  
\> \> to reset as the value of the next sequence number  
\> \> immediately following the messages and/or  
\> \> sequence numbers being skipped”  
\> \> -FIX4.2 Spec (with errata 20010501)  
\> \>  
\> \>  
\> \> Say I’ve already sent messages 1-100.  
\> \>  
\> \> When responding to a resend request for messages  
\> \> 50-75 (assuming 50-75 are administrative) do I  
\> \> send a GapFill with:  
\> \>  
\> \> A. MsgSeqNum=50 NewSeqNo=76  
\> \>  
\> \> or  
\> \>  
\> \> B. MsgSeqNum=50 NewSeqNo=101  
\> \>  
\> \>  
\> \>  
\> \> I think “A” because 76 is the next sequence number  
\> \> immediately following the messages being skipped  
\> \> (50-75).  
\> \>  
\> \> I have a vender which is expecting “B” and I was wondering if this breaks the protocol.  
\> \>  
\> \> Any input is appreciated. Thanks.  
\> \>  
\> \> Thanks.  
\> \>  
\> \> -------------------------------------------------  
\> \> Tim A. Olson  
\> \> [tolson@manfinancial.com](mailto:tolson@manfinancial.com)  
\> \>  
\> \>  
\>