Hi Justin, Thanks for the clarification. I agree to your point ,but consider a use-case if I have routing decision only based on destination ip then as per current implementation, ovs will add 2 flows (in data path)for packets coming from different source and if the TTL happens to be different for them .This will reduce number of flows that can be supported with ovs. If decrement TTL was done in kernel ,it would have ended in adding one flow only.
Regards, Bindiya Regards, Bindiya On Tue, Aug 27, 2019 at 9:48 PM Justin Pettit <[email protected]> wrote: > I think it was considered cleaner from an ABI perspective, since it > doesn't require another action, since "set" was already supported. In > practice, I don't think it's a problem, since usually a TTL decrement is > associated with a routing decision, and TTLs tend to be fairly static > between two hosts. > > --Justin > > > > On Aug 27, 2019, at 1:11 AM, bindiya Kurle <[email protected]> > wrote: > > > > hi , > > I have a question related to dec_ttl action implemented in datapath. > > when dec_ttl action is configured in OVS following action get added in > datapath. > > > > recirc_id(0),in_port(2),eth(),eth_type(0x0800),ipv4(ttl=64,frag=no), > packets:3, bytes:294, used:0.068s, actions:set(ipv4(ttl=63)),3, > > > > if packet comes with different TTL on same port then one more action get > added in datapath. > > for ex: > > recirc_id(0),in_port(2),eth(),eth_type(0x0800),ipv4(ttl=9,frag=no), > packets:3, bytes:294, used:0.068s, actions:set(ipv4(ttl=8)),3, > > > > Could someone please explain why dec_ttl is implemeted as a set action > rather than dec_ttl action. > > > > > > I mean , why for different ttl one more rule get added rather than just > adding it as following as done in userspace > > > > recirc_id(0),in_port(3),eth(),eth_type(0x0800),ipv4(frag=no), packets:3, > bytes:294, used:0.737s, actions:dec_ttl,2 > > > > Regards, > > Bindiya > > _______________________________________________ > > discuss mailing list > > [email protected] > > https://mail.openvswitch.org/mailman/listinfo/ovs-discuss > >
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