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Diffstat (limited to 'src/plugins/lb/lb_plugin_doc.md')
| -rw-r--r-- | src/plugins/lb/lb_plugin_doc.md | 33 |
1 files changed, 21 insertions, 12 deletions
diff --git a/src/plugins/lb/lb_plugin_doc.md b/src/plugins/lb/lb_plugin_doc.md index c7885ffb837..7672b1e88d7 100644 --- a/src/plugins/lb/lb_plugin_doc.md +++ b/src/plugins/lb/lb_plugin_doc.md @@ -8,19 +8,26 @@ Wich also means feedback is really welcome regarding features, apis, etc... ## Overview -This plugin provides load balancing for VPP in a way that is largely inspired +This plugin provides load balancing for VPP in a way that is largely inspired from Google's MagLev: http://research.google.com/pubs/pub44824.html -The load balancer is configured with a set of Virtual IPs (VIP, which can be +The load balancer is configured with a set of Virtual IPs (VIP, which can be prefixes), and for each VIP, with a set of Application Server addresses (ASs). +There are four encap types to steer traffic to different ASs: +1). IPv4+GRE ad IPv6+GRE encap types: Traffic received for a given VIP (or VIP prefix) is tunneled using GRE towards -the different ASs in a way that (tries to) ensure that a given session will +the different ASs in a way that (tries to) ensure that a given session will always be tunneled to the same AS. +2). IPv4+L3DSR encap types: +L3DSR is used to overcome Layer 2 limitations of Direct Server Return Load Balancing. +It maps VIP to DSCP bits, and reuse TOS bits to transfer DSCP bits +to server, and then server will get VIP from DSCP-to-VIP mapping. + Both VIPs or ASs can be IPv4 or IPv6, but for a given VIP, all ASs must be using -the same encap. type (i.e. IPv4+GRE or IPv6+GRE). Meaning that for a given VIP, -all AS addresses must be of the same family. +the same encap. type (i.e. IPv4+GRE or IPv6+GRE or IPv4+L3DSR). +Meaning that for a given VIP, all AS addresses must be of the same family. ## Performances @@ -35,34 +42,36 @@ in next versions. The load balancer needs to be configured with some parameters: - lb conf [ip4-src-address <addr>] [ip6-src-address <addr>] + lb conf [ip4-src-address <addr>] [ip6-src-address <addr>] [buckets <n>] [timeout <s>] - + ip4-src-address: the source address used to send encap. packets using IPv4. ip6-src-address: the source address used to send encap. packets using IPv6. buckets: the *per-thread* established-connexions-table number of buckets. -timeout: the number of seconds a connection will remain in the +timeout: the number of seconds a connection will remain in the established-connexions-table while no packet for this flow is received. - ### Configure the VIPs - lb vip <prefix> [encap (gre6|gre4)] [new_len <n>] [del] - + lb vip <prefix> [encap (gre6|gre4|l3dsr)] [dscp <n>] [new_len <n>] [del] + new_len is the size of the new-connection-table. It should be 1 or 2 orders of magnitude bigger than the number of ASs for the VIP in order to ensure a good load balancing. +Encap l3dsr and dscp is used to map VIP to dscp bit and rewrite DSCP bit in packets. +So the selected server could get VIP from DSCP bit in this packet and perform DSR. Examples: - + lb vip 2002::/16 encap gre6 new_len 1024 lb vip 2003::/16 encap gre4 new_len 2048 lb vip 80.0.0.0/8 encap gre6 new_len 16 lb vip 90.0.0.0/8 encap gre4 new_len 1024 + lb vip 100.0.0.0/8 encap l3dsr dscp 2 new_len 32 ### Configure the ASs (for each VIP) |