Need to increase TWAMP MBZ integer to 2 Bytes
twamp.test.mbz1 MBZ Unsigned integer (1 byte)
Is there any way to edit this filter to support 2 byte field? Routers will insert values greater than 255.
On Cisco routers, MBZ field is 16 bits
"MBZ" stands for "Must Be Zero"; the only value an MBZ value can have is zero (which is less than 255...), so either this field is not an MBZ field, and its value may have some significance, or those routers have buggy firmware/oftware.
MBZ needs to be corrected and reworded to Session ID. I suppose this is an interpretation of Wireshark which is not correct.
RFC 5357 shows the fields as
MBZ.In Cisco's implementation, the MBZ field is the Session-ID. Without it, the control plane would not be able to differentiate between sessions. All TWAMP sessions originated in the router use the same UDP socket.
I can let the MIG BU know about this RFC discrepancy and get their feedback.
If there's any chance that 1) the MBZ field in question gets assigned a use in a future RFC and 2) the Cisco device might send packets to, or receive packets from, a device that implements that future RFC, and the conflicting use of that field would cause a problem, they might want to think about this, including getting that field specified as for use by a session ID.
No, it's an interpretation by Wireshark that follows the official specification rather than following a vendor's private extension of that specification.
I got a response for MIG BU. TWAMP packets sent over SRTE for liveness detection follow the RFC 8972 - Simple Two-Way Active Measurement Protocol Optional Extensions
In this RFC, TWAMP packets carry the Session ID - 16 bits. Would it make sense to create a separate decoder for these packets?