networking-sfc

The type of service function

Asked by Vincent Chao

Hi,

I would like to know some concepts about service function.
What kind of service function does networking-sfc expect to chain?
I mean, some firewall could have ability to receive packets with other dst_MAC. (like promiscuous mode)
But in the networking-sfc project, It rewrite the dst_mac before ingress service function.
That means the last service function before the destination node must have ability to rewrite the "dst_mac" of packet header to original destination node's MAC
If no, destination node will receive the packets with last SF's dst mac and drop it.
Could someone give me some example of service function?
I am building networking-sfc with devstack, but i have no idea to prepare a service function.

Thank you very much

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Language:
English Edit question
Status:
Solved
For:
networking-sfc Edit question
Assignee:
Louis Fourie Edit question
Solved by:
Louis Fourie
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Revision history for this message
Louis Fourie (lfourie) said : 		#1

A simple SF can be created using a VM with IP forwarding:

sysctl -w net.ipv4.ip_forward=1

Revision history for this message
Vincent Chao (vc-answer) said : 		#2

Thanks for the answer.
A simple SF can be created using IP forwarding or openvswitch.
But I'm trying to say what a real SF looks like.
Does the last SF need to rewrite the dst-mac to the destination.
In this project, It seems yes.

[src-node] --->[SF] ------->[dst-node]
                                       ↑
                                       │
                                   packets still with SF dst-mac

In my opinion, A SF should not take dst-mac into account.

Revision history for this message
Best Louis Fourie (lfourie) said : 		#3

No, the last SF does not need to re-write the destination MAC

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Vincent Chao (vc-answer) said : 		#4

Thanks Louis Fourie, that solved my question.