[ovs-dev] [PATCH 1/8] nsh: datapath support for network service headers

Jarno Rajahalme jrajahalme at nicira.com
Tue Oct 1 18:03:28 UTC 2013


On Oct 1, 2013, at 10:07 AM, Pritesh Kothari (pritkoth) <pritkoth at cisco.com> wrote:

> 
> On Sep 30, 2013, at 5:46 PM, Jesse Gross wrote:
> 
>> On Fri, Sep 20, 2013 at 1:04 AM, pritesh <pritesh.kothari at cisco.com> wrote:
>>> This patch adds support for Network Service Headers (nsh) over VXLAN
>>> as mentioned in [1]. Here changes are made to datapath to add nsh
>>> headers whenever a vxlan port with destination port as 9030 is created.
>>> IANA port allocation for nsh over vxlan is yet to be done.
>> 
>> I'm pretty concerned about using a magic UDP port, especially since
>> one hasn't been allocated yet (we went through the same situation with
>> VXLAN itself). Is there a way that we can just insert/remove this
>> header on a flow basis?
> 
> you mean adding/removing headers when nsh specific parameters (nsp/nsi)
> are set while creating/editing a port? or should i just add a toggle nsh=true
> instead of port number till it is finalized?
> 

Or just insert NSH when the relevant attributes are set for the flow. In data path, instead of using the port number to determine wether the NSH header should be included, use the TUNNEL_NSP flag. On reception it would be good if the presence of NSH could be detected from the headers/payload without a special UDP port number, so that same tunnel port could be used for receiving NSH from some tunnels, and non-NSH payloads from others. This seems trivially doable with GRE, but I'm not entirely sure if that is possible with vxlan (without the special UDP port, that is).

  Jarno


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