I saw it as: The pain we see is in the network, host solutions don't
(as of yet) provide the control required for large-scale TE issues
[...]
Hi Chris -
On the other hand, RRG does have several host-based multi-homing
solutions that enable the network to exercise traffic engineering:
Six/One gives the network explicit traffic engineering control through
address prefix rewrites in routers. Multi-path TCP gives the network an
implicit means for traffic engineering through bandwidth limits and
packet loss. And both Six/One and multi-path TCP can be used within the
framework of a hostname-oriented network protocol stack.
The only argument that can be brought up against host-based multi-homing
is that it becomes effective only if a considerable portion of all hosts
supports it. Even if networks can ensure that local hosts do support
multi-homing, there is still a dependency on remote hosts supporting it
as well. However, the dependency on the remote side does exist also for
network-based multi-homing. Like host-based multi-homing, network-based
multi-homing does require support on both sides of a connection.
Consequently, host-based multi-homing is IMO deployment-wise just as
feasible as network-based multi-homing. And technically, host-based
multi-homing is IMO even preferable for two reasons: (a) It is
inherently more robust because it does not add new single points of
failure. (b) It is more reliable because only hosts can monitor the
availability of complete end-to-end paths.
FWIW: The above considerations apply only to RRG's goal of enabling
multi-homing. They do NOT apply to RRG's second goal of eliminating
renumbering. Eliminating renumbering entirely is possible only with a
network-based solution. And unlike enabling multi-homing, eliminating
renumbering is achievable with only unilateral support: Six/One Router
Unilateral mode and NAT66 are example solutions. Since the first goal
can IMO best be solved in hosts, whereas the second goal is achievable
only with a network-based solution, I was suggesting the dual approach
consisting of a host-based solution plus a network-based solution.
- Christian
_______________________________________________
rrg mailing list
[email protected]
https://www.irtf.org/mailman/listinfo/rrg
