Re: [dpdk-users] Issue with UDP based fragmented packets on Azure cloud

[Raslan Darawsheh <rasland@nvidia.com>]

Hi,

> -----Original Message-----
> From: users <users-bounces@dpdk.org> On Behalf Of madhukar mythri
> Sent: Thursday, May 27, 2021 5:58 PM
> To: users@dpdk.org
> Subject: [dpdk-users] Issue with UDP based fragmented packets on Azure
> cloud
> 
> Hi,
> 
> We are facing issue with UDP/IP based fragmented packets on Azure cloud
> platform with Accelerated-Network enabled ports.
> 
> UDP fragmented Rx packets were able to receive well on media ports. But,
> when two fragmented packet received, first fragment is received on Queue-
> 0
> and second fragment is received on Queue-1. Ideally all the fragments(of
> single large packet) should be received single queue based on RSS, so that
> we can re-assemble as single pkt and process it, which is working well in
> other platforms on KVM hyper-visors(with I40evf NIC’s).
> 
> I think, the as per RSS hash cacluation all the fragmented pkts should
> reach on single-queue(because the 5-tuple hash value will be same), but
> this is not happening in-case of Azue VM's Why ?
> 
> Does anybody faced similar issue, please let me know your suggestion.
I guess it depends on the fragments themselves, 
If your first fragment contains a UDP header (the first frag in the list)  then the RSS hash will be on the full 5 tuble 
Src/dst IP and src/dst udp 
But, for the other frags you'll not get src/dst udp since they are not present in the pkt.
I guess you should be using only RSS On IP header to make all frags go to the same queue.
> 
> Thanks,
> Madhukar.
 

Kindest regards,
Raslan Darawsheh