# several FIX sessions with same SenderCompId/TargetCompId

**URL:** <https://forum.fixtrading.org/t/several-fix-sessions-with-same-sendercompid-targetcompid/4542>\
**Category:** General Q&A\
**Tags:** general-qa, imported, xid\_167625\
**Created:** [July 2, 2008, 11:15am UTC](https://forum.fixtrading.org/t/several-fix-sessions-with-same-sendercompid-targetcompid/4542 "2008-07-02T11:15:25Z")\
**Posts on this page:** 5\
**Page:** 1

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**Author:** ![carlosmartin\_x](https://avatars.discourse-cdn.com/v4/letter/c/d2c977/32.png) [@carlosmartin\_x](https://forum.fixtrading.org/u/carlosmartin_x)\
**Post date:** [July 2, 2008, 11:15am UTC](https://forum.fixtrading.org/t/several-fix-sessions-with-same-sendercompid-targetcompid/4542/1 "2008-07-02T11:15:25Z")

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Imported from previous forum

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<div class="post-metadata">

**Author:** ![carlosmartin\_x](https://avatars.discourse-cdn.com/v4/letter/c/d2c977/32.png) [@carlosmartin\_x](https://forum.fixtrading.org/u/carlosmartin_x)\
**Post date:** [July 2, 2008, 11:15am UTC](https://forum.fixtrading.org/t/several-fix-sessions-with-same-sendercompid-targetcompid/4542/2 "2008-07-02T11:15:25Z")

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Hi all.

I’ve searched information about having several FIX session with same SenderCompId/targetcompId , but i found nothing. Anyone knows if having such configuration is correct with FIX specification ?

We usually have different SendercompId/TargetCompId values for each FIX session, and i thought that was the right thing .

Anyone knows where can i found information about this in the FIX speceification?

Regards  
Carlos Martin

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<div class="post-metadata">

**Author:** ![fplpo\_x](https://avatars.discourse-cdn.com/v4/letter/f/7ab992/32.png) [@fplpo\_x](https://forum.fixtrading.org/u/fplpo_x)\
**Post date:** [July 2, 2008, 1:23pm UTC](https://forum.fixtrading.org/t/several-fix-sessions-with-same-sendercompid-targetcompid/4542/3 "2008-07-02T13:23:55Z")

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[original email was from John Prewett - [jprewett@lavatrading.com](mailto:jprewett@lavatrading.com) ]  
\> Hi all.

> I’ve searched information about having several FIX session with same  
> SenderCompId/targetcompId , but i found nothing. Anyone knows if having  
> such configuration is correct with FIX specification ?
> 
> We usually have different SendercompId/TargetCompId values for each FIX  
> session, and i thought that was the right thing .
> 
> Anyone knows where can i found information about this in the FIX  
> specification?
> 
> Regards Carlos Martin

I don’t believe there is anything in the specification that would preclude using two sessions with identical Sender/Target CompIDs.  
It would be up to both sides to keep these sessions separate with respect to message processing, sequence numbers etc,.

That said, I believe it would be entirely unwise to do such a thing.

The primary way to identify a specific session is using the Sender/Target CompIDs. Imagine calling the other side of the FIX session and requesting that they reset sequence numbers. How would you identify which session you want to reset?

Using the same Sender/Target CompIDs for more than one session sounds like an accident waiting to happen.

If someone is requesting multiple sessions with the same Sender/Target CompIDs, perhaps you should ask them why. If the problem is spreading the load across a couple of FIX engines because one cannot keep up with the required throughput, may I suggest varying either Sender or Target CompID (or both):  
Originally: SenderCompID=MyCorp; TargetCompID=YourCorp.  
Proposed session #1: SenderCompID=MyCorp1; TargetCompID=YourCorp1.  
Proposed session #2: SenderCompID=MyCorp2; TargetCompID=YourCorp2.

It’s not cast in stone as to precisely what a Sender/TargetCompID needs to be. It’s good to use something that clearly identifies the sender or receiver. Adding a 1 or 2 or whatever on the end of that won’t alter the fact that a human can still easily determine who it is.

I hope this helps.

John Prewett

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<div class="post-metadata">

**Author:** ![carlosmartin\_x](https://avatars.discourse-cdn.com/v4/letter/c/d2c977/32.png) [@carlosmartin\_x](https://forum.fixtrading.org/u/carlosmartin_x)\
**Post date:** [July 2, 2008, 2:46pm UTC](https://forum.fixtrading.org/t/several-fix-sessions-with-same-sendercompid-targetcompid/4542/4 "2008-07-02T14:46:38Z")

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> > Hi all.
> > 
> > I’ve searched information about having several FIX session with same  
> > SenderCompId/targetcompId , but i found nothing. Anyone knows if  
> > having such configuration is correct with FIX specification ?
> > 
> > We usually have different SendercompId/TargetCompId values for each  
> > FIX session, and i thought that was the right thing .
> > 
> > Anyone knows where can i found information about this in the FIX  
> > specification?
> > 
> > Regards Carlos Martin
> 
> I don’t believe there is anything in the specification that would  
> preclude using two sessions with identical Sender/Target CompIDs. It  
> would be up to both sides to keep these sessions separate with respect  
> to message processing, sequence numbers etc,.
> 
> That said, I believe it would be entirely unwise to do such a thing.
> 
> The primary way to identify a specific session is using the  
> Sender/Target CompIDs. Imagine calling the other side of the FIX session  
> and requesting that they reset sequence numbers. How would you identify  
> which session you want to reset?
> 
> Using the same Sender/Target CompIDs for more than one session sounds  
> like an accident waiting to happen.
> 
> If someone is requesting multiple sessions with the same Sender/Target  
> CompIDs, perhaps you should ask them why. If the problem is spreading  
> the load across a couple of FIX engines because one cannot keep up with  
> the required throughput, may I suggest varying either Sender or Target  
> CompID (or both): Originally: SenderCompID=MyCorp;  
> TargetCompID=YourCorp. Proposed session #1: SenderCompID=MyCorp1;  
> TargetCompID=YourCorp1. Proposed session #2: SenderCompID=MyCorp2;  
> TargetCompID=YourCorp2.
> 
> It’s not cast in stone as to precisely what a Sender/TargetCompID needs  
> to be. It’s good to use something that clearly identifies the sender or  
> receiver. Adding a 1 or 2 or whatever on the end of that won’t alter the  
> fact that a human can still easily determine who it is.
> 
> I hope this helps.
> 
> John Prewett

Thanks

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<div class="post-metadata">

**Author:** ![souravbanerjee\_x](https://avatars.discourse-cdn.com/v4/letter/s/8baadc/32.png) [@souravbanerjee\_x](https://forum.fixtrading.org/u/souravbanerjee_x)\
**Post date:** [July 4, 2008, 7:38am UTC](https://forum.fixtrading.org/t/several-fix-sessions-with-same-sendercompid-targetcompid/4542/5 "2008-07-04T07:38:13Z")

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Yes,  
In general only SendercompId, TargetcomId pair should be sufficient. However FIX Message-header contain several other tags which u can use for your specific requirement.

SenderSubId (tag 50)  
TargetSubId (tag 57 )  
SenderLocationId ( tag 142 )  
TargetLocationId ( tag 143)

The other party should also need to implement the same tags.

for more details on these tags please refer FIX Documents.

regards,

Sourav Banerjee.

* * *

> Hi all.
> 
> I’ve searched information about having several FIX session with same  
> SenderCompId/targetcompId , but i found nothing. Anyone knows if having  
> such configuration is correct with FIX specification ?
> 
> We usually have different SendercompId/TargetCompId values for each FIX  
> session, and i thought that was the right thing .
> 
> Anyone knows where can i found information about this in the FIX  
> speceification?
> 
> Regards Carlos Martin