Regarding INAP parameter Tags

classic Classic list List threaded Threaded
1 message Options
Reply | Threaded
Open this post in threaded view
Report Content as Inappropriate

Regarding INAP parameter Tags

prabath weerasinghe
Hi All,

This is regarding INAP PDU encoding and decoding. I'm working on an INAP protocol implementation and was referring  ASN.1 specification. Here follows an excerpt from the spec for InitialDP.

InitialDPArg ::= SEQUENCE {
 serviceKey [0] ServiceKey,
 calledPartyNumber [2] CalledPartyNumber OPTIONAL,
 callingPartyNumber [3] CallingPartyNumber OPTIONAL,
 callingPartysCategory [5] CallingPartysCategory OPTIONAL,
 cGEncountered [7] CGEncountered OPTIONAL,
 iPSSPCapabilities [8] IPSSPCapabilities OPTIONAL,

As per the specification, serviceKey has the tag value of 0 and calledPartyNumber has a tag value of 2 an so on. When I checked a sample INAP pcap
INAP-Sample-PCAP , it was showing the tag values for serviceKey and calledPartyNumber as 80 and 82 in Hex. 
Could anyone please explain the reason for the difference ?  Is there any special way of encoding the tag value ?

Thanks and Regards,
Prabath Weerasinghe

Confidentiality and Disclaimer

This email and any attachments are intended only for the person or entity to whom it is addressed. Its contents may be privileged, confidential or otherwise protected from disclosure. If you are not the intended recipient, please do not read, disclose, distribute or copy this email or use the information therein or act or omit to act in reliance thereof. Please also inform the sender of erroneous receipt and delete the material from your system.

Sigtran mailing list
[hidden email]