Hi Duraivelan, see my answers below: > On Dec 18, 2018, at 4:42 AM, Duraivelan Chockalingam <[email protected]> > wrote: > > Hi > I would like to have this clarified, on my question about Metadata > Let us say, I have an Open Flow rules, as below > > Cookie=0x8000001, duration=228925.445s, table=17, n_packets=350, > n_bytes=32424, priority=10,metadata=0xc000f30000000000/0xffffff0000000000 > actions=goto_table:19 > > I wanted to understand the following > > I believe these Metadata Values are determined by the ODL
Metadata is a way for a switch to mark a packet and make local routing decisions based on that. The flow is programmed by ODL so yes ODL decides the metadata. > > Do we have certain rule/ Algorithm , to determine these Metadata from a > Packet. > Because the Actual Packet in OVS is actually switched based on Matching > Metadata, Is that correct ?? ( Atleast according to the rule ) > And the Packet itself does not carry the Metadata. Metadata only exists in the context of the local switch so you cannot for instance match an incoming packet using metadata or set a metadata to an outgoing packet, but you can for example match a packet, set metadata on it and then send the packet to another table for further processing based in metadata. > > Then how exactly the packet hitting a flow matched against the Metadata. As explained earlier same switch sets metadata and matches metadata. > If I understood it correctly the Packets those are traversed between the > flow, are within the OVS application itself or Handled @OVS Application > level, until it had determined Egress Port > So in that Case, the MetaData are handled @OVS-Application level, until the > Packets is send via Egress Port. Yes, metadata is only used internally in the switch. > > Finally which Module in ODL is responsible for determine the Metadata, and I > would like to understand from the code how exactly it was done. OpenFlow applications can use or not metadata, if you are interested in the topic I would recommend you to reach an application/project that uses metadata (e.g. netvirt, SFC, etc) and ask how they use it. > > > Thanks for your time, and clarification, and sorry if it is too much. > > _______________________________________________ > openflowplugin-dev mailing list > [email protected] > https://lists.opendaylight.org/mailman/listinfo/openflowplugin-dev
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