Re: [Tsv-art] [tram] Tsvart last call review of draft-ietf-tram-turnbis-25

[Joe Touch <[e-mail]>]

Tiru,

This sort of patch isn’t sufficient. It doesn’t address the confusion throughout section 15 as to what’s actually happening.

Sec 15 shouldn’t talk about “setting” IP header values at all; it should refer to “configuring transport sessions” in the desired ways. Otherwise you’re implying direct packet-level conversion. Even the title of that section is a problem in this regard.

Tthe sections themselves should be revised to similarly refer to transport-level actions, not packet level, e.g.:
15.1 TCP to UDP
	- because DSCP should not vary within a TCP session, there is no packet-level tracking of copying DSCP from TCP to UDP; instead, DSCP would be a property of the TCP session that would be used to configure the UDP socket pair.
	- IP fragmentation control needs to be explained in terms of UDP interactions
	- IPv6 fragmentation has nothing to do with the received packet (which is TCP
	- IP options are *as default*; it’ isn’t correct that you never use IP options (or are you actively disabling them?)
		NOTE: that goes for the direct IPv4 to IPv6 translation in section 4 (which is similarly problematic)

15.2 UDP to TCP
	- the last sentence of the second paragraph seems at odds with the first; the first says “set these once per connection”, it is sufficient IMO.
	-TCP DSCP should be based on the *first* UDP value seen (it could vary)
	- same issue with IP extension headers and options (presumably you use the default

Joe

> On Jun 19, 2019, at 8:14 AM, Konda, Tirumaleswar Reddy <[e-mail]> wrote:
> 
> Hi Joe,
>  
> The IPv4 and IPv6 fragmentation description is specific to TCP-to-UDP relaying between the client and the peer (only for TCP-to-UDP relay, the DF attribute in the TURN message will be used to set the DF bit in the outgoing UDP packet to the peer). To avoid confusion, I have added two new sub-sections:
> 15.1.  IP Header Fields for TCP-to-UDP relaying and 15.2 IP Header Fields for UDP-to-TCP relaying
>  
> Please see the attached updated draft.
>  
> Cheers,
> -Tiru