Group Tables
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Next, there is the SELECT group, which is primarily designed for load balancing. As indicated in the following figure, each bucket in a SELECT group has an assigned weight, and each packet that enters the group is sent to a single bucket. The bucket selection algorithm is undefined and is dependent on the switch’s implementation; however, weighted round robin is perhaps the most obvious and simplest choice of packet distribution to buckets. The weight of a bucket is provided as a special parameter to each bucket. Each bucket in a SELECT group is still a list of actions, so any actions supported by OpenFlow can be used in each bucket, and the buckets need not be uniform.
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PicOS does not support weight. Because OVS forward is based on priority of entries in TCAM, the traditional ECMP in routing table cannot be used. For a typical IP flow, PicOS implements a "dummy ECMP" by splitting the matching fields of a flow. For a group-table with type=select, PicOS support set-select-group-hash-fields and the packets will hash according to the value of set-select-group-hash-fields. |
The command added for setting select-group hash fields is:
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1. If the match field does not include dl_type=0x0800. set-select-group-hash-fields: dl_src,dl_dst admin@PicOS-OVS$ovs-vsctl set-select-group-hash-fields dl_src,dl_dst admin@PicOS-OVS$ovs-vsctl show-select-group-hash-fields select_group_hash_fields: dl_src,dl_dst 1> There is no dl_src or dl_dst in flow match field, use dl_src for hashing, admin@PicOS-OVS$ovs-ofctl add-group br0 group_id=1,type=select,bucket=output:14,bucket=output:25,bucket=output:38 admin@PicOS-OVS$ovs-ofctl add-flow br0 in_port=1,actions=group:1 admin@PicOS-OVS$ admin@PicOS-OVS$ovs-appctl pica/dump-flows #4 normal permanent recirc_id=0,in_port=1,dl_src=00:00:00:00:00:01/00:00:00:00:00:03, actions:25 #5 normal permanent recirc_id=0,in_port=1,dl_src=00:00:00:00:00:00/00:00:00:00:00:03, actions:14 #2 normal permanent recirc_id=0,in_port=1,dl_src=00:00:00:00:00:03/00:00:00:00:00:03, actions:14 #3 normal permanent recirc_id=0,in_port=1,dl_src=00:00:00:00:00:02/00:00:00:00:00:03, actions:38 2> dl_src has hashable mask in flow match field, use dl_src for hashing, admin@PicOS-OVS$ovs-ofctl add-group br0 group_id=1,type=select,bucket=output:14,bucket=output:25,bucket=output:38 admin@PicOS-OVS$ovs-ofctl add-flow br0 in_port=1,dl_src=22:11:11:1100:1100:00/ff:ff:ff:00:00:00,actions=group:1 admin@PicOS-OVS$ admin@PicOS-OVS$ovs-appctl pica/dump-flows #9 normal permanent recirc_id=0,in_port=1,dl_src=22:11:11:00:00:00/ff:ff:ff:00:00:03, actions:14 #8 normal permanent recirc_id=0,in_port=1,dl_src=22:11:11:00:00:01/ff:ff:ff:00:00:03, actions:25 #7 normal permanent recirc_id=0,in_port=1,dl_src=22:11:11:00:00:02/ff:ff:ff:00:00:03, actions:38 #6 normal permanent recirc_id=0,in_port=1,dl_src=22:11:11:00:00:03/ff:ff:ff:00:00:03, actions:14 3> dl_src has no hashable mask and there is no dl_dst in flow match field, use dl_dst for hashing, admin@PicOS-OVS$ovs-ofctl add-group br0 group_id=1,type=select,bucket=output:14,bucket=output:25,bucket=output:38 admin@PicOS-OVS$ovs-ofctl add-flow br0 in_port=1,dl_src=22:11:11:11:11:11,actions=group:1 admin@PicOS-OVS$ admin@PicOS-OVS$ovs-appctl pica/dump-flows #13 normal permanent recirc_id=0,in_port=1,dl_src=22:11:11:11:11:11,dl_dst=00:00:00:00:00:00/00:00:00:00:00:03, actions:14 #12 normal permanent recirc_id=0,in_port=1,dl_src=22:11:11:11:11:11,dl_dst=00:00:00:00:00:01/00:00:00:00:00:03, actions:25 #11 normal permanent recirc_id=0,in_port=1,dl_src=22:11:11:11:11:11,dl_dst=00:00:00:00:00:02/00:00:00:00:00:03, actions:38 #10 normal permanent recirc_id=0,in_port=1,dl_src=22:11:11:11:11:11,dl_dst=00:00:00:00:00:03/00:00:00:00:00:03, actions:14 4> There is no dl_src, and dl_dst has hashable mask in flow match field, use dl_src for hashing, admin@PicOS-OVS$ovs-ofctl add-group br0 group_id=1,type=select,bucket=output:14,bucket=output:25,bucket=output:38 admin@PicOS-OVS$ovs-ofctl add-flow br0 in_port=1,dl_dst=22:22:22:00:00:00/ff:ff:ff:00:00:00,actions=group:1 admin@PicOS-OVS$ admin@PicOS-OVS$ovs-appctl pica/dump-flows #83 normal permanent recirc_id=0,in_port=1,dl_src=00:00:00:00:00:01/00:00:00:00:00:03,dl_dst=22:22:22:00:00:00/ff:ff:ff:00:00:00, actions:25 #81 normal permanent recirc_id=0,in_port=1,dl_src=00:00:00:00:00:03/00:00:00:00:00:03,dl_dst=22:22:22:00:00:00/ff:ff:ff:00:00:00, actions:14 #84 normal permanent recirc_id=0,in_port=1,dl_src=00:00:00:00:00:00/00:00:00:00:00:03,dl_dst=22:22:22:00:00:00/ff:ff:ff:00:00:00, actions:14 #82 normal permanent recirc_id=0,in_port=1,dl_src=00:00:00:00:00:02/00:00:00:00:00:03,dl_dst=22:22:22:00:00:00/ff:ff:ff:00:00:00, actions:38 5> dl_src and dl_dst have no hashable mask in flow match field, won't hash, admin@PicOS-OVS$ovs-ofctl add-group br0 group_id=1,type=select,bucket=output:14,bucket=output:25,bucket=output:38 admin@PicOS-OVS$ovs-ofctl add-flow br0 in_port=1,dl_src=22:11:11:11:11:11,dl_dst=22:22:22:22:22:22,actions=group:1 admin@PicOS-OVS$ admin@PicOS-OVS$ovs-appctl pica/dump-flows #18 normal permanent recirc_id=0,in_port=1,dl_src=22:11:11:11:11:11,dl_dst=22:22:22:22:22:22, actions:14 2. If the match field include dl_type=0x0800. set-select-group-hash-fields: nw_dst,nw_src, admin@PicOS-OVS$ovs-vsctl set-select-group-hash-fields nw_dst,nw_src admin@PicOS-OVS$ovs-vsctl show-select-group-hash-fields select_group_hash_fields: nw_dst,nw_src 1> There is no nw_dst or nw_src in flow match field, use nw_dst for hashing, admin@PicOS-OVS$ovs-ofctl add-group br0 group_id=1,type=select,bucket=output:14,bucket=output:25,bucket=output:38 admin@PicOS-OVS$ovs-ofctl add-flow br0 in_port=1,dl_type=0x0800,actions=group:1 admin@PicOS-OVS$ admin@PicOS-OVS$ovs-appctl pica/dump-flows #28 normal permanent recirc_id=0,ip,in_port=1,nw_dst=0.0.0.2/0.0.0.3, actions:38 #30 normal permanent recirc_id=0,ip,in_port=1,nw_dst=0.0.0.0/0.0.0.3, actions:14 #29 normal permanent recirc_id=0,ip,in_port=1,nw_dst=0.0.0.1/0.0.0.3, actions:25 #27 normal permanent recirc_id=0,ip,in_port=1,nw_dst=0.0.0.3/0.0.0.3, actions:14 2> nw_dst has hashable mask, use nw_dst for hashing, admin@PicOS-OVS$ovs-ofctl add-group br0 group_id=1,type=select,bucket=output:14,bucket=output:25,bucket=output:38 admin@PicOS-OVS$ovs-ofctl add-flow br0 in_port=1,dl_type=0x0800,nw_dst=192.168.2.0/24,actions=group:1 admin@PicOS-OVS$ admin@PicOS-OVS$ovs-appctl pica/dump-flows #35 normal permanent recirc_id=0,ip,in_port=1,nw_dst=192.168.2.3/255.255.255.3, actions:14 #37 normal permanent recirc_id=0,ip,in_port=1,nw_dst=192.168.2.1/255.255.255.3, actions:25 #38 normal permanent recirc_id=0,ip,in_port=1,nw_dst=192.168.2.0/255.255.255.3, actions:14 #36 normal permanent recirc_id=0,ip,in_port=1,nw_dst=192.168.2.2/255.255.255.3, actions:38 3> nw_dst has no hashable mask and there is no nw_src in match field, use nw_src for hashing, admin@PicOS-OVS$ovs-ofctl add-group br0 group_id=1,type=select,bucket=output:14,bucket=output:25,bucket=output:38 admin@PicOS-OVS$ovs-ofctl add-flow br0 in_port=1,dl_type=0x0800,nw_dst=192.168.2.100,actions=group:1 admin@PicOS-OVS$ admin@PicOS-OVS$ovs-appctl pica/dump-flows #40 normal permanent recirc_id=0,ip,in_port=1,nw_src=0.0.0.2/0.0.0.3,nw_dst=192.168.2.100, actions:38 #42 normal permanent recirc_id=0,ip,in_port=1,nw_src=0.0.0.0/0.0.0.3,nw_dst=192.168.2.100, actions:14 #41 normal permanent recirc_id=0,ip,in_port=1,nw_src=0.0.0.1/0.0.0.3,nw_dst=192.168.2.100, actions:25 #39 normal permanent recirc_id=0,ip,in_port=1,nw_src=0.0.0.3/0.0.0.3,nw_dst=192.168.2.100, actions:14 4> There is no nw_dst, and nw_src has hashable mask, use nw_dst for hashing, admin@PicOS-OVS$ovs-ofctl add-group br0 group_id=1,type=select,bucket=output:14,bucket=output:25,bucket=output:38 admin@PicOS-OVS$ovs-ofctl add-flow br0 in_port=1,dl_type=0x0800,nw_src=192.168.1.0/24,actions=group:1 admin@PicOS-OVS$ admin@PicOS-OVS$ovs-appctl pica/dump-flows #46 normal permanent recirc_id=0,ip,in_port=1,nw_src=192.168.1.0/24,nw_dst=0.0.0.1/0.0.0.3, actions:25 #44 normal permanent recirc_id=0,ip,in_port=1,nw_src=192.168.1.0/24,nw_dst=0.0.0.3/0.0.0.3, actions:14 #47 normal permanent recirc_id=0,ip,in_port=1,nw_src=192.168.1.0/24,nw_dst=0.0.0.0/0.0.0.3, actions:14 #45 normal permanent recirc_id=0,ip,in_port=1,nw_src=192.168.1.0/24,nw_dst=0.0.0.2/0.0.0.3, actions:38 5> nw_src and nw_dst have no hashable mask in match field, won't hash, admin@PicOS-OVS$ovs-ofctl add-group br0 group_id=1,type=select,bucket=output:14,bucket=output:25,bucket=output:38 admin@PicOS-OVS$ovs-ofctl add-flow br0 in_port=1,dl_type=0x0800,nw_src=192.168.1.100,nw_dst=192.168.2.100,actions=group:1 admin@PicOS-OVS$ admin@PicOS-OVS$ovs-appctl pica/dump-flows #48 normal permanent recirc_id=0,ip,in_port=1,nw_src=192.168.1.100,nw_dst=192.168.2.100, actions:14 3. set-select-group-hash-fields: nw_src,dl_src admin@PicOS-OVS$ovs-vsctl set-select-group-hash-fields nw_src,dl_src admin@PicOS-OVS$ovs-vsctl show-select-group-hash-fields select_group_hash_fields: nw_src,dl_src admin@PicOS-OVS$ovs-ofctl add-group br0 group_id=1,type=select,bucket=output:12,bucket=output:13,bucket=output:14 admin@PicOS-OVS$ovs-ofctl add-flow br0 in_port=11,ip,nw_src=10.10.10.10,nw_dst=10.10.20.0/24,dl_src=00:00:00:11:11:00/ff:ff:ff:ff:ff:00,dl_dst=00:00:00:22:22:22,actions=group:1 The order is "nw_src, dl_src", so will check the first filed "nw_src" and find all mask bits of nw_src in flow entry are "1", in order will check the second filed "dl_src" find the some mask bits are not "1", then the hardware flow entry will hash by "dl_src". admin@PicOS-OVS$ admin@PicOS-OVS$ovs-appctl pica/dump-flows #29 normal permanent recirc_id=0,ip,in_port=11,dl_src=00:00:00:11:11:00/ff:ff:ff:ff:ff:03,dl_dst=00:00:00:22:22:22,nw_src=10.10.10.10,nw_dst=10.10.20.0/24, actions:12 #27 normal permanent recirc_id=0,ip,in_port=11,dl_src=00:00:00:11:11:02/ff:ff:ff:ff:ff:03,dl_dst=00:00:00:22:22:22,nw_src=10.10.10.10,nw_dst=10.10.20.0/24, actions:14 #28 normal permanent recirc_id=0,ip,in_port=11,dl_src=00:00:00:11:11:01/ff:ff:ff:ff:ff:03,dl_dst=00:00:00:22:22:22,nw_src=10.10.10.10,nw_dst=10.10.20.0/24, actions:13 #26 normal permanent recirc_id=0,ip,in_port=11,dl_src=00:00:00:11:11:03/ff:ff:ff:ff:ff:03,dl_dst=00:00:00:22:22:22,nw_src=10.10.10.10,nw_dst=10.10.20.0/24, actions:12 4. set-select-group-hash-fields: nw_src,dl_dst admin@PicOS-OVS$ovs-vsctl set-select-group-hash-fields nw_src,dl_dst admin@PicOS-OVS$ovs-vsctl show-select-group-hash-fields select_group_hash_fields: nw_src,dl_dst admin@PicOS-OVS$ovs-ofctl add-group br0 group_id=1,type=select,bucket=output:12,bucket=output:13,bucket=output:14 admin@PicOS-OVS$ovs-ofctl add-flow br0 in_port=11,ip,nw_src=10.10.10.10,nw_dst=10.10.20.0/24,dl_src=00:00:00:11:11:00/ff:ff:ff:ff:ff:00,dl_dst=00:00:00:22:22:22,actions=group:1 The order is "nw_src, dl_dst", so will check the first filed "nw_src" and find all mask bits of nw_src in flow entry are "1", in order will check the second filed "dl_dst" find all the mask bits are "1", selected field in this time then only one bucket can be used. admin@PicOS-OVS$ovs-appctl pica/dump-flows #30 normal permanent recirc_id=0,ip,in_port=11,dl_src=00:00:00:11:11:00/ff:ff:ff:ff:ff:00,dl_dst=00:00:00:22:22:22,nw_src=10.10.10.10,nw_dst=10.10.20.0/24, actions:14 |
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