Colby, you are, as far as I can tell, correct that the potential for
state explosion is extremely risky and requires careful management.
That is why the bestbar draft emphasis that the state is abotu slice
aggregates, not end-to-end slices, and probably not even individual IETF
network slices.
Yours,
Joel
On 2/2/2021 2:19 PM, Colby Barth wrote:
Tarek, indeed …
draft-bestbar-spring-scalable-ns-00 provides a relevant example of the rather
enormous amount of state the solution described in
draft-dong-spring-sr-for-enhanced-vpn results in:
"Notably, this approach requires maintaining per slice state for each
topological element on every router in the network in both the
control and data plane. For example, a network composed of 'N'
nodes, where each node has up to 'K' adjacencies to its neighbors, a
node would have to assign and advertise 'M' Slice Prefix-SIDs and 'M'
Slice Adjacency-SID(s) to each of it 'K' adjacencies. Consequently,
a router will have to maintain up to (N+K)*M SIDs in the control
plane, and an equal number of label routes in its forwarding plane."
Put in practical terms, this implicitly limits the number of VTNs or, in
draft-bestbar-teas-ns-packet-01 terminology, the number of Slice aggregates
that can be offered. It also introduces a dependency between the network size
and the number of VTNs. i.e. the larger the network, the smaller the number of
VTNs that can be supported.
—Colby
On Feb 2, 2021, at 12:54 PM, Tarek Saad <tsaad=40juniper....@dmarc.ietf.org>
wrote:
Hi Eduard,
Inline..
On 2/2/21, 10:50 AM, "spring on behalf of Vasilenko Eduard" <spring-boun...@ietf.org on behalf of vasilenko.edu...@huawei.com> wrote:
Hi all,
There is the general trend to encode the action into the packet, not to
distribute states in the control plane for all possible traffic types.
Granularity, programmability are better.
[TS]: Indeed, we are in agreement on encoding the information in packet as opposed to distributing states in the control plane. In draft-bestbar-spring-scalable-ns, a separate ID inside the packet is proposed to carry the needed information. However, this draft <draft-dong-spring-sr-for-enhanced-vpn> is proposing distributing per VTN state in the network which is completely against your argument ...
Regards,
Tarek
This type of virtualization is fully in-line with this trend.
Support.
Eduard
From: spring [mailto:spring-boun...@ietf.org] On Behalf Of James Guichard
Sent: Wednesday, January 27, 2021 12:47 PM
To: spring@ietf.org
Cc: spring-cha...@ietf.org
Subject: [spring] WG Adoption Call for draft-dong-spring-sr-for-enhanced-vpn
Dear WG:
This message starts a 2 week WG adoption call for https://datatracker.ietf.org/doc/draft-dong-spring-sr-for-enhanced-vpn/ ending February 10th 2021.
After review of the document please indicate support (or not) for WG adoption to the mailing list and if you are willing to work on the document, please state this explicitly. This gives the chairs an indication of the energy level of people in the working group willing to work on this document. Please also provide comments/reasons for your support (or lack thereof) as this is a stronger way to indicate your (non) support as this is not a vote.
Thanks!
Jim, Bruno & Joel
Juniper Business Use Only
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