Hi Lucy.
Lucy yong <[email protected]> writes:
> Section 5.3 describes gateways. IMO: it misses an important use
> case. A Gateway, say overlay gateway, may be used to interconnect
> two or more overlay VNs. In this case, the traffic traversing
> between two overlay VNs must go through the gateway where the
> policy can be enforced. Furthermore, it is possible to implement
> centralized or distributed overlay gateway. The latter has overlay
> gateway function implemented on NVEs. Thus, it requests the
> cross-VN policies to be distributed to NVEs.
> Current section seems very focus on overlay VN interconnect a
> non-overlay network, which centralized gateway architecture is
> practical. But in overlay networks, both centralized or distributed
> are possible and depend on the applications.
Agreed. I propose adding a new section after 5.3 that says:
<section title="Distributed Gateways">
<t>
The relaying of traffic from one VN to another deserves
special consideration. The previous section described
gateways performing this function. If such gateways are
centralized, traffic between TSes on different VNs can take
suboptimal paths, i.e., triangular routing results in paths
that always traverse the gateway. As an optimization,
individual NVEs can be part of a distributed gateway that
performs such relaying, reducing or completely eliminating
triangular routing. In a distributed gateway, each ingress
NVE can perform such relaying activity directly, so long as
it has access to the policy information needed to determine
whether cross-VN communication is allowed. Having individual
NVEs be part of a distributed gateway allows them to tunnel
traffic directly to the destination NVE without the need to
take suboptimal paths.
</t>
<t>
The NVO3 architecture should [must? or just say it does?]
support distributed gateways. Such support requires that
NVO3 control protocols include mechanisms for the
maintenance and distribution of policy information about
what type of cross-VN communication is allowed so that NVEs
acting as distributed gateways can tunnel traffic from one
VN to another as appropriate.
</t>
</section>
Thoughts?
Thomas
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