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From: roopa <roopa@cumulusnetworks•com>
To: Robert Shearman <rshearma@brocade•com>
Cc: netdev@vger•kernel.org,
	"Eric W. Biederman" <ebiederm@xmission•com>,
	Thomas Graf <tgraf@suug•ch>,
	Dinesh Dutt <ddutt@cumulusnetworks•com>,
	Vivek Venkatraman <vivek@cumulusnetworks•com>
Subject: Re: [RFC net-next 3/3] mpls: new ipmpls device for encapsulating IP packets as mpls
Date: Tue, 02 Jun 2015 11:57:21 -0700	[thread overview]
Message-ID: <556DFC91.1090708@cumulusnetworks.com> (raw)
In-Reply-To: <556DDAEF.9080209@brocade.com>

On 6/2/15, 9:33 AM, Robert Shearman wrote:
> On 02/06/15 17:15, roopa wrote:
>> On 6/1/15, 9:46 AM, Robert Shearman wrote:
>>> Allow creating an mpls device for the purposes of encapsulating IP
>>> packets with:
>>>
>>>    ip link add type ipmpls
>>>
>>> This device defines its per-nexthop encapsulation data as a stack of
>>> labels, in the same format as for RTA_NEWST. It uses the encap data
>>> which will have been stored in the IP route to encapsulate the packet
>>> with that stack of labels, with the last label corresponding to a
>>> local label that defines how the packet will be sent out. The device
>>> sends packets over loopback to the local MPLS forwarding logic which
>>> performs all of the work.
>>>
>>>
>> Maybe a silly question, but when you loop the packet back, what does the
>> local MPLS forwarding logic
>> lookup with ? It probably assumes there is a mpls route with that label
>> and nexthop.
>> Will this need any internal labels (thinking same label stack different
>> tunnel device etc) ?
>
> Yes, it requires that local/internal labels have been allocated and 
> label routes installed in the label table for them.
This is our only concern.
>
> It is entirely possible to put the outgoing interface into the encap 
> data to avoid having to allocate extra labels, 
> but I did it this way in order to support PIC Core for MPLS-VPN routes.

hmm..., is a netdevice must in this case.., can you please elaborate on 
this ?.

>
> Note: I have two extra patches which avoid using the loopback device 
> (which causes the TTL to end up being one less than it should on 
> output), but I haven't posted them here because they were dependent on 
> other mpls changes in my tree.

ok, thanks.

  reply	other threads:[~2015-06-02 18:57 UTC|newest]

Thread overview: 32+ messages / expand[flat|nested]  mbox.gz  Atom feed  top
2015-06-01 16:46 [RFC net-next 0/3] IP imposition of per-nh MPLS encap Robert Shearman
2015-06-01 16:46 ` [RFC net-next 1/3] net: infra for per-nexthop encap data Robert Shearman
2015-06-02 18:15   ` Eric W. Biederman
2015-06-01 16:46 ` [RFC net-next 2/3] ipv4: storing and retrieval of per-nexthop encap Robert Shearman
2015-06-02 16:01   ` roopa
2015-06-02 16:35     ` Robert Shearman
2015-06-01 16:46 ` [RFC net-next 3/3] mpls: new ipmpls device for encapsulating IP packets as mpls Robert Shearman
2015-06-02 16:15   ` roopa
2015-06-02 16:33     ` Robert Shearman
2015-06-02 18:57       ` roopa [this message]
2015-06-02 21:06         ` Robert Shearman
2015-06-03 18:43           ` Vivek Venkatraman
2015-06-04 18:46             ` Robert Shearman
2015-06-04 21:38               ` Vivek Venkatraman
2015-06-02 18:26   ` Eric W. Biederman
2015-06-02 21:37     ` Thomas Graf
2015-06-02 22:48       ` Eric W. Biederman
2015-06-02 23:23       ` Eric W. Biederman
2015-06-03  9:50         ` Thomas Graf
2015-06-02  0:06 ` [RFC net-next 0/3] IP imposition of per-nh MPLS encap Thomas Graf
2015-06-02 13:28   ` Robert Shearman
2015-06-02 21:43     ` Thomas Graf
2015-06-03 13:30       ` Robert Shearman
2015-06-02 15:31 ` roopa
2015-06-02 18:30   ` Eric W. Biederman
2015-06-02 18:39     ` roopa
2015-06-02 18:11 ` Eric W. Biederman
2015-06-02 20:57   ` Robert Shearman
2015-06-02 21:10     ` Eric W. Biederman
2015-06-02 22:15       ` Robert Shearman
2015-06-02 22:58         ` Eric W. Biederman
2015-06-04 15:12           ` Nicolas Dichtel

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