[Ryu-devel] Debug Group Table - Round Robin for Select Group Type

[Clément R. <rau...@gm...>]

Hi,

Is there a way to see if a group entry has been used (i.e. if a packet
has been sent to this entry) and which bucket action has been
selected?

Because I'm experiencing something weird with a group.

Packets towards 11.0.0.2 (with vlan tag to 1) arrive at switch 6 and I
wrote a group entry to match them.

 curl -X POST -d '{
    "dpid": 6,
    "type": "SELECT",
    "group_id": 1,
    "buckets": [
                    {
                    "weight": 1,
                    "watch_port": 1,
                    "actions": [
                        {
                            "type": "OUTPUT",
                            "port": 1
                        }
                                ]
                    },
                    {
                    "weight": 1,
                    "watch_port": 2,
                    "actions": [
                        {
                            "type": "OUTPUT",
                            "port": 2
                        }
                                ]
                    },
                    {
                    "weight": 1,
                    "watch_port": 3,
                    "actions": [
                        {
                            "type": "OUTPUT",
                            "port": 3
                        }
                                ]
                    },
                    {
                    "weight": 1,
                    "watch_port": 4,
                    "actions": [
                        {
                            "type": "OUTPUT",
                            "port": 4
                        }
                                ]
                    }
                ]
 }' http://localhost:8080/stats/groupentry/add

 curl -X POST -d '{
    "dpid": 6,
    "cookie": 1,
    "cookie_mask": 1,
    "table_id": 0,
    "idle_timeout": 0,
    "hard_timeout": 0,
    "priority": 11112,
    "flags": 1,
    "match":{
        "nw_dst": "11.0.0.2",
        "eth_type": 2048,
        "vlan_vid": 1
    },
    "actions":[
        {
            "type":"GROUP",
            "group_id": 1
        }
            ]
 }' http://localhost:8080/stats/flowentry/add

But when I inspect with wireshark the packets are not sent to any
outport and I don't understand why.

I wrote a flow entry to see if I was matching correctly on them:

  curl -X POST -d '{
    "dpid": 6,
    "cookie": 1,
    "cookie_mask": 1,
    "table_id": 0,
    "idle_timeout": 0,
    "hard_timeout": 0,
    "priority": 11113,
    "flags": 1,
    "match":{
        "nw_dst": "11.0.0.2",
        "eth_type": 2048,
        "vlan_vid": 1
    },
    "actions":[
        {
        "type":"OUTPUT",
        "port": 4
        }
            ]
 }' http://localhost:8080/stats/flowentry/add

And it worked, after adding this entry all packets were sent to outport 4.

So I guess there is a problem with the group that I wrote but I don't
know what...


What is the standard behaviour for a select group type?

>From the documentation I understood that it's a round robin mechanism
but when I investigate it it looks like all the packets are always
taking the first bucket (live).

How can I achieve a round robin behaviour then? I thought that I just
need to put the same weight to each action bucket.

Best,
Clément