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Diffstat (limited to 'src/plugins/srv6-ad')
| -rw-r--r-- | src/plugins/srv6-ad/ad_plugin_doc.md | 73 | ||||
| -rw-r--r-- | src/plugins/srv6-ad/ad_plugin_doc.rst | 86 |
2 files changed, 86 insertions, 73 deletions
diff --git a/src/plugins/srv6-ad/ad_plugin_doc.md b/src/plugins/srv6-ad/ad_plugin_doc.md deleted file mode 100644 index 993eeb63589..00000000000 --- a/src/plugins/srv6-ad/ad_plugin_doc.md +++ /dev/null @@ -1,73 +0,0 @@ -# SRv6 endpoint to SR-unaware appliance via dynamic proxy (End.AD) {#srv6_ad_plugin_doc} - -## Overview - -The dynamic proxy is an improvement over the static proxy (@ref srv6_as_plugin_doc) -that dynamically learns the SR information before removing it from the incoming -traffic. The same information can then be re-attached to the traffic returning -from the SF. As opposed to the static SR proxy, no CACHE information needs to be -configured. Instead, the dynamic SR proxy relies on a local caching mechanism on -the node instantiating this segment. Therefore, a dynamic proxy segment cannot -be the last segment in an SR SC policy. A different SR behavior should thus be -used if the SF is meant to be the final destination of an SR SC policy. - -Upon receiving a packet whose active segment matches a dynamic SR proxy -function, the proxy node pops the top MPLS label or applies the SRv6 End -behavior, then compares the updated SR information with the cache entry for the -current segment. If the cache is empty or different, it is updated with the new -SR information. The SR information is then removed and the inner packet is sent -towards the SF. - -The cache entry is not mapped to any particular packet, but instead to an SR SC -policy identified by the receiving interface (IFACE-IN). Any non-link-local IP -packet or non-local Ethernet frame received on that interface will be -re-encapsulated with the cached headers as described in @ref srv6_as_plugin_doc. The -SF may thus drop, modify or generate new packets without affecting the proxy. - -For more information, please see -[draft-xuclad-spring-sr-service-chaining](https://datatracker.ietf.org/doc/draft-xuclad-spring-sr-service-chaining/). - -## CLI configuration - -The following command instantiates a new End.AD segment that sends the inner -packets on interface `IFACE-OUT` towards an appliance at address `S-ADDR` and -restores the encapsulation headers of the packets coming back on interface -`IFACE-IN`. - -``` -sr localsid address SID behavior end.ad nh S-ADDR oif IFACE-OUT iif IFACE-IN -``` - -For example, the below command configures the SID `1::A1` with an End.AD -function for sending traffic on interface `GigabitEthernet0/8/0` to the -appliance at address `A1::`, and receiving it back on interface -`GigabitEthernet0/9/0`. - -``` -sr localsid address 1::A1 behavior end.ad nh A1:: oif GigabitEthernet0/8/0 iif GigabitEthernet0/9/0 -``` - -## Pseudocode - -The dynamic proxy SRv6 pseudocode is obtained by inserting the following -instructions between lines 1 and 2 of the static proxy SRv6 pseudocode. - -``` -IF NH=SRH & SL > 0 THEN - Decrement SL and update the IPv6 DA with SRH[SL] - IF C(IFACE-IN) different from IPv6 encaps THEN ;; Ref1 - Copy the IPv6 encaps into C(IFACE-IN) ;; Ref2 -ELSE - Drop the packet -``` - -**Ref1:** "IPv6 encaps" represents the IPv6 header and any attached extension -header. - -**Ref2:** C(IFACE-IN) represents the cache entry associated to the dynamic SR proxy -segment. It is identified with IFACE-IN in order to efficiently retrieve the -right SR information when a packet arrives on this interface. - -In addition, the inbound policy should check that C(IFACE-IN) has been defined -before attempting to restore the IPv6 encapsulation, and drop the packet -otherwise. diff --git a/src/plugins/srv6-ad/ad_plugin_doc.rst b/src/plugins/srv6-ad/ad_plugin_doc.rst new file mode 100644 index 00000000000..cfb6cea7a15 --- /dev/null +++ b/src/plugins/srv6-ad/ad_plugin_doc.rst @@ -0,0 +1,86 @@ +.. _srv6_ad_plugin_doc: + +SRv6 dynamic proxy +================== + +SRv6 endpoint to SR-unaware appliance via dynamic proxy (End.AD) +---------------------------------------------------------------- + +Overview +~~~~~~~~ + +The dynamic proxy is an improvement over the static proxy (@ref +srv6_as_plugin_doc) that dynamically learns the SR information before +removing it from the incoming traffic. The same information can then be +re-attached to the traffic returning from the SF. As opposed to the +static SR proxy, no CACHE information needs to be configured. Instead, +the dynamic SR proxy relies on a local caching mechanism on the node +instantiating this segment. Therefore, a dynamic proxy segment cannot be +the last segment in an SR SC policy. A different SR behavior should thus +be used if the SF is meant to be the final destination of an SR SC +policy. + +Upon receiving a packet whose active segment matches a dynamic SR proxy +function, the proxy node pops the top MPLS label or applies the SRv6 End +behavior, then compares the updated SR information with the cache entry +for the current segment. If the cache is empty or different, it is +updated with the new SR information. The SR information is then removed +and the inner packet is sent towards the SF. + +The cache entry is not mapped to any particular packet, but instead to +an SR SC policy identified by the receiving interface (IFACE-IN). Any +non-link-local IP packet or non-local Ethernet frame received on that +interface will be re-encapsulated with the cached headers as described +in @ref srv6_as_plugin_doc. The SF may thus drop, modify or generate new +packets without affecting the proxy. + +For more information, please see +`draft-xuclad-spring-sr-service-chaining <https://datatracker.ietf.org/doc/draft-xuclad-spring-sr-service-chaining/>`__. + +CLI configuration +~~~~~~~~~~~~~~~~~ + +The following command instantiates a new End.AD segment that sends the +inner packets on interface ``IFACE-OUT`` towards an appliance at address +``S-ADDR`` and restores the encapsulation headers of the packets coming +back on interface ``IFACE-IN``. + +:: + + sr localsid address SID behavior end.ad nh S-ADDR oif IFACE-OUT iif IFACE-IN + +For example, the below command configures the SID ``1::A1`` with an +End.AD function for sending traffic on interface +``GigabitEthernet0/8/0`` to the appliance at address ``A1::``, and +receiving it back on interface ``GigabitEthernet0/9/0``. + +:: + + sr localsid address 1::A1 behavior end.ad nh A1:: oif GigabitEthernet0/8/0 iif GigabitEthernet0/9/0 + +Pseudocode +~~~~~~~~~~ + +The dynamic proxy SRv6 pseudocode is obtained by inserting the following +instructions between lines 1 and 2 of the static proxy SRv6 pseudocode. + +:: + + IF NH=SRH & SL > 0 THEN + Decrement SL and update the IPv6 DA with SRH[SL] + IF C(IFACE-IN) different from IPv6 encaps THEN ;; Ref1 + Copy the IPv6 encaps into C(IFACE-IN) ;; Ref2 + ELSE + Drop the packet + +**Ref1:** “IPv6 encaps” represents the IPv6 header and any attached +extension header. + +**Ref2:** C(IFACE-IN) represents the cache entry associated to the +dynamic SR proxy segment. It is identified with IFACE-IN in order to +efficiently retrieve the right SR information when a packet arrives on +this interface. + +In addition, the inbound policy should check that C(IFACE-IN) has been +defined before attempting to restore the IPv6 encapsulation, and drop +the packet otherwise. |