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diff --git a/docs/report/introduction/methodology_nat44.rst b/docs/report/introduction/methodology_nat44.rst deleted file mode 100644 index 7dfd939ecc..0000000000 --- a/docs/report/introduction/methodology_nat44.rst +++ /dev/null @@ -1,487 +0,0 @@ -.. _nat44_methodology: - -Network Address Translation IPv4 to IPv4 -^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^ - -NAT44 Prefix Bindings -~~~~~~~~~~~~~~~~~~~~~ - -NAT44 prefix bindings should be representative to target applications, -where a number of private IPv4 addresses from the range defined by -:rfc:`1918` is mapped to a smaller set of public IPv4 addresses from the -public range. - -Following quantities are used to describe inside to outside IP address -and port bindings scenarios: - -- Inside-addresses, number of inside source addresses - (representing inside hosts). -- Ports-per-inside-address, number of TCP/UDP source - ports per inside source address. -- Outside-addresses, number of outside (public) source addresses - allocated to NAT44. -- Ports-per-outside-address, number of TCP/UDP source - ports per outside source address. The maximal number of - ports-per-outside-address usable for NAT is 64 512 - (in non-reserved port range 1024-65535, :rfc:`4787`). -- Sharing-ratio, equal to inside-addresses divided by outside-addresses. - -CSIT NAT44 tests are designed to take into account the maximum number of -ports (sessions) required per inside host (inside-address) and at the -same time to maximize the use of outside-address range by using all -available outside ports. With this in mind, the following scheme of -NAT44 sharing ratios has been devised for use in CSIT: - -+--------------------------+---------------+ -| ports-per-inside-address | sharing-ratio | -+==========================+===============+ -| 63 | 1024 | -+--------------------------+---------------+ -| 126 | 512 | -+--------------------------+---------------+ -| 252 | 256 | -+--------------------------+---------------+ -| 504 | 128 | -+--------------------------+---------------+ - -Initial CSIT NAT44 tests, including associated TG/TRex traffic profiles, -are based on ports-per-inside-address set to 63 and the sharing ratio of -1024. This approach is currently used for all NAT44 tests including -NAT44det (NAT44 deterministic used for Carrier Grade NAT applications) -and NAT44ed (Endpoint Dependent). - -.. - TODO: Will we ever test other than 63 ports-per-inside-address? - TODO: Will we ever NAT44ei? What about NAT66, NAT64, NAT46? - -Private address ranges to be used in tests: - -- 192.168.0.0 - 192.168.255.255 (192.168/16 prefix) - - - Total of 2^16 (65 536) of usable IPv4 addresses. - - Used in tests for up to 65 536 inside addresses (inside hosts). - -- 172.16.0.0 - 172.31.255.255 (172.16/12 prefix) - - - Total of 2^20 (1 048 576) of usable IPv4 addresses. - - Used in tests for up to 1 048 576 inside addresses (inside hosts). - -NAT44 Session Scale -``````````````````` - -NAT44 session scale tested is govern by the following logic: - -- Number of inside-addresses(hosts) H[i] = (H[i-1] x 2^2) with H(0)=1 024, - i = 1,2,3, ... - - - H[i] = 1 024, 4 096, 16 384, 65 536, 262 144, ... - -- Number of sessions S[i] = H[i] * ports-per-inside-address - - - ports-per-inside-address = 63 - -+---+---------+------------+ -| i | hosts | sessions | -+===+=========+============+ -| 0 | 1 024 | 64 512 | -+---+---------+------------+ -| 1 | 4 096 | 258 048 | -+---+---------+------------+ -| 2 | 16 384 | 1 032 192 | -+---+---------+------------+ -| 3 | 65 536 | 4 128 768 | -+---+---------+------------+ -| 4 | 262 144 | 16 515 072 | -+---+---------+------------+ - -NAT44 Deterministic -``````````````````` - -NAT44det performance tests are using TRex STL (Stateless) API and traffic -profiles, similar to all other stateless packet forwarding tests like -ip4, ip6 and l2, sending UDP packets in both directions -inside-to-outside and outside-to-inside. See -:ref:`data_plane_throughput` for more detail. - -The inside-to-outside traffic uses single destination address (20.0.0.0) -and port (1024). -The inside-to-outside traffic covers whole inside address and port range, -the outside-to-inside traffic covers whole outside address and port range. - -.. - TODO: Clarify outside-to-inside source and destination address+port. - -NAT44det translation entries are created during the ramp-up phase, -followed by verification that all entries are present, -before proceeding to the main measurements of the test. -This ensures session setup does not impact the forwarding performance test. - -Associated CSIT test cases use the following naming scheme to indicate -NAT44det scenario tested: - -- ethip4udp-nat44det-h{H}-p{P}-s{S}-[mrr|ndrpdr|soak] - - - {H}, number of inside hosts, H = 1024, 4096, 16384, 65536, 262144. - - {P}, number of ports per inside host, P = 63. - - {S}, number of sessions, S = 64512, 258048, 1032192, 4128768, - 16515072. - - [mrr|ndrpdr|soak], MRR, NDRPDR or SOAK test. - -.. - TODO: The -s{S} part is redundant, - we can save space by removing it. - TODO: Rename nat44det suites so it is clear they are throughput (not cps). - TODO: Make traffic profile names resemble suite names more closely. - -NAT44 Endpoint-Dependent -```````````````````````` - -In order to excercise NAT44ed ability to translate based on both -source and destination address and port, the inside-to-outside traffic -varies also destination address and port. Destination port is the same -as source port, destination address has the same offset as the source address, -but applied to different subnet (starting with 20.0.0.0). - -As the mapping is not deterministic (for security reasons), -we cannot easily use stateless bidirectional traffic profiles. -Inside address and port range is fully covered, -but we do not know which outside-to-inside source address and port to use -to hit an open session. - -Therefore, NAT44ed is benchmarked using following methodologies: - -- Unidirectional throughput using *stateless* traffic profile. -- Connections-per-second (CPS) using *stateful* traffic profile. -- Bidirectional throughput (TPUT, see below) using *stateful* traffic profile. - -Unidirectional NAT44ed throughput tests are using TRex STL (Stateless) -APIs and traffic profiles, but with packets sent only in -inside-to-outside direction. -Similarly to NAT44det, NAT44ed unidirectional throughput tests include -a ramp-up phase to establish and verify the presence of required NAT44ed -binding entries. As the sessions have finite duration, the test code -keeps inserting ramp-up trials during the search, if it detects a risk -of sessions timing out. Any zero loss trial visits all sessions, -so it acts also as a ramp-up. - -Stateful NAT44ed tests are using TRex ASTF (Advanced Stateful) APIs and -traffic profiles, with packets sent in both directions. Tests are run -with both UDP and TCP sessions. -As NAT44ed CPS (connections-per-second) stateful tests -measure (also) session opening performance, -they use state reset instead of ramp-up trial. -NAT44ed TPUT (bidirectional throughput) tests prepend ramp-up trials -as in the unidirectional tests, -so the test results describe performance without translation entry -creation overhead. - -Associated CSIT test cases use the following naming scheme to indicate -NAT44det case tested: - -- Stateless: ethip4udp-nat44ed-h{H}-p{P}-s{S}-udir-[mrr|ndrpdr|soak] - - - {H}, number of inside hosts, H = 1024, 4096, 16384, 65536, 262144. - - {P}, number of ports per inside host, P = 63. - - {S}, number of sessions, S = 64512, 258048, 1032192, 4128768, - 16515072. - - udir-[mrr|ndrpdr|soak], unidirectional stateless tests MRR, NDRPDR - or SOAK. - -- Stateful: ethip4[udp|tcp]-nat44ed-h{H}-p{P}-s{S}-[cps|tput]-[mrr|ndrpdr|soak] - - - [udp|tcp], UDP or TCP sessions - - {H}, number of inside hosts, H = 1024, 4096, 16384, 65536, 262144. - - {P}, number of ports per inside host, P = 63. - - {S}, number of sessions, S = 64512, 258048, 1032192, 4128768, - 16515072. - - [cps|tput], connections-per-second session establishment rate or - packets-per-second average rate, or packets-per-second rate - without session establishment. - - [mrr|ndrpdr|soak], bidirectional stateful tests MRR, NDRPDR, or SOAK. - -Stateful traffic profiles -~~~~~~~~~~~~~~~~~~~~~~~~~ - -There are several important details which distinguish ASTF profiles -from stateless profiles. - -General considerations -`````````````````````` - -Protocols -_________ - -ASTF profiles are limited to either UDP or TCP protocol. - -Programs -________ - -Each template in the profile defines two "programs", one for the client side -and one for the server side. - -Each program specifies when that side has to wait until enough data is received -(counted in packets for UDP and in bytes for TCP) -and when to send additional data. Together, the two programs -define a single transaction. Due to packet loss, transaction may take longer, -use more packets (retransmission) or never finish in its entirety. - -Instances -_________ - -A client instance is created according to TPS parameter for the trial, -and sends the first packet of the transaction (in some cases more packets). -Each client instance uses a different source address (see sequencing below) -and some source port. The destination address also comes from a range, -but destination port has to be constant for a given program. - -TRex uses an opaque way to chose source ports, but as session counting shows, -next client with the same source address uses a different source port. - -Server instance is created when the first packet arrives to the server side. -Source address and port of the first packet are used as destination address -and port for the server responses. This is the ability we need -when outside surface is not predictable. - -When a program reaches its end, the instance is deleted. -This creates possible issues with server instances. If the server instance -does not read all the data client has sent, late data packets -can cause a second copy of server instance to be created, -which breaks assumptions on how many packet a transaction should have. - -The need for server instances to read all the data reduces the overall -bandwidth TRex is able to create in ASTF mode. - -Note that client instances are not created on packets, -so it is safe to end client program without reading all server data -(unless the definition of transaction success requires that). - -Sequencing -__________ - -ASTF profiles offer two modes for choosing source and destination IP addresses -for client programs: seqential and pseudorandom. -In current tests we are using sequential addressing only (if destination -address varies at all). - -For client destination UDP/TCP port, we use a single constant value. -(TRex can support multiple program pairs in the same traffic profile, -distinguished by the port number.) - -Transaction overlap -___________________ - -If a transaction takes longer to finish, compared to period implied by TPS, -TRex will have multiple client or server instances active at a time. - -During calibration testing we have found this increases CPU utilization, -and for high TPS it can lead to TRex's Rx or Tx buffers becoming full. -This generally leads to duration stretching, and/or packet loss on TRex. - -Currently used transactions were chosen to be short, so risk of bad behavior -is decreased. But in MRR tests, where load is computed based on NIC ability, -not TRex ability, anomalous behavior is still possible -(e.g. MRR values being way lower than NDR). - -Delays -______ - -TRex supports adding constant delays to ASTF programs. -This can be useful, for example if we want to separate connection establishment -from data transfer. - -But as TRex tracks delayed instances as active, this still results -in higher CPU utilization and reduced performance issues -(as other overlaping transactions). So the current tests do not use any delays. - -Keepalives -__________ - -Both UDP and TCP protocol implementations in TRex programs support keepalive -duration. That means there is a configurable period of keepalive time, -and TRex sends keepalive packets automatically (outside the program) -for the time the program is active (started, not ended yet) -but not sending any packets. - -For TCP this is generally not a big deal, as the other side usually -retransmits faster. But for UDP it means a packet loss may leave -the receiving program running. - -In order to avoid keepalive packets, keepalive value is set to a high number. -Here, "high number" means that even at maximum scale and minimum TPS, -there are still no keepalive packets sent within the corresponding -(computed) trial duration. This number is kept the same also for -smaller scale traffic profiles, to simplify maintenance. - -Transaction success -___________________ - -The transaction is considered successful at Layer-7 (L7) level -when both program instances close. At this point, various L7 counters -(unofficial name) are updated on TRex. - -We found that proper close and L7 counter update can be CPU intensive, -whereas lower-level counters (ipackets, opackets) called L2 counters -can keep up with higher loads. - -For some tests, we do not need to confirm the whole transaction was successful. -CPS (connections per second) tests are a typical example. -We care only for NAT44ed creating a session (needs one packet -in inside-to-outside direction per session) and being able to use it -(needs one packet in outside-to-inside direction). - -Similarly in TPUT tests (packet throuput, counting both control -and data packets), we care about NAT44ed ability to forward packets, -we do not care whether aplications (TRex) can fully process them at that rate. - -Therefore each type of tests has its own formula (usually just one counter -already provided by TRex) to count "successful enough" transactions -and attempted transactions. Currently, all tests relying on L7 counters -use size-limited profiles, so they know what the count of attempted -transactions should be, but due to duration stretching -TRex might have been unable to send that many packets. -For search purposes, unattempted transactions are treated the same -as attempted but failed transactions. - -Sometimes even the number of transactions as tracked by search algorithm -does not match the transactions as defined by ASTF programs. -See TCP TPUT profile below. - -UDP CPS -``````` - -This profile uses a minimalistic transaction to verify NAT44ed session has been -created and it allows outside-to-inside traffic. - -Client instance sends one packet and ends. -Server instance sends one packet upon creation and ends. - -In principle, packet size is configurable, -but currently used tests apply only one value (100 bytes frame). - -Transaction counts as attempted when opackets counter increases on client side. -Transaction counts as successful when ipackets counter increases on client side. - -TCP CPS -``````` - -This profile uses a minimalistic transaction to verify NAT44ed session has been -created and it allows outside-to-inside traffic. - -Client initiates TCP connection. Client waits until connection is confirmed -(by reading zero data bytes). Client ends. -Server accepts the connection. Server waits for indirect confirmation -from client (by waiting for client to initiate close). Server ends. - -Without packet loss, the whole transaction takes 7 packets to finish -(4 and 3 per direction). -From NAT44ed point of view, only the first two are needed to verify -the session got created. - -Packet size is not configurable, but currently used tests report -frame size as 64 bytes. - -Transaction counts as attempted when tcps_connattempt counter increases -on client side. -Transaction counts as successful when tcps_connects counter increases -on client side. - -UDP TPUT -```````` - -This profile uses a small transaction of "request-response" type, -with several packets simulating data payload. - -Client sends 5 packets and closes immediately. -Server reads all 5 packets (needed to avoid late packets creating new -server instances), then sends 5 packets and closes. -The value 5 was chosen to mirror what TCP TPUT (see below) choses. - -Packet size is configurable, currently we have tests for 100, -1518 and 9000 bytes frame (to match size of TCP TPUT data frames, see below). - -As this is a packet oriented test, we do not track the whole -10 packet transaction. Similarly to stateless tests, we treat each packet -as a "transaction" for search algorthm packet loss ratio purposes. -Therefore a "transaction" is attempted when opacket counter on client -or server side is increased. Transaction is successful if ipacket counter -on client or server side is increased. - -If one of 5 client packets is lost, server instance will get stuck -in the reading phase. This probably decreases TRex performance, -but it leads to more stable results then alternatives. - -TCP TPUT -```````` - -This profile uses a small transaction of "request-response" type, -with some data amount to be transferred both ways. - -In CSIT release 22.06, TRex behavior changed, so we needed to edit -the traffic profile. Let us describe the pre-22.06 profile first. - -Client connects, sends 5 data packets worth of data, -receives 5 data packets worth of data and closes its side of the connection. -Server accepts connection, reads 5 data packets worth of data, -sends 5 data packets worth of data and closes its side of the connection. -As usual in TCP, sending side waits for ACK from the receiving side -before proceeding with next step of its program. - -Server read is needed to avoid premature close and second server instance. -Client read is not stricly needed, but ACKs allow TRex to close -the server instance quickly, thus saving CPU and improving performance. - -The number 5 of data packets was chosen so TRex is able to send them -in a single burst, even with 9000 byte frame size (TRex has a hard limit -on initial window size). -That leads to 16 packets (9 of them in c2s direction) to be exchanged -if no loss occurs. -The size of data packets is controlled by the traffic profile setting -the appropriate maximum segment size. Due to TRex restrictions, -the minimal size for IPv4 data frame achievable by this method is 70 bytes, -which is more than our usual minimum of 64 bytes. -For that reason, the data frame sizes available for testing are 100 bytes -(that allows room for eventually adding IPv6 ASTF tests), -1518 bytes and 9000 bytes. There is no control over control packet sizes. - -Exactly as in UDP TPUT, ipackets and opackets counters are used for counting -"transactions" (in fact packets). - -If packet loss occurs, there can be large transaction overlap, even if most -ASTF programs finish eventually. This can lead to big duration stretching -and somehow uneven rate of packets sent. This makes it hard to interpret -MRR results (frequently MRR is below NDR for this reason), -but NDR and PDR results tend to be stable enough. - -In 22.06, the "ACK from the receiving side" behavior changed, -the receiving side started sending ACK sometimes -also before receiving the full set of 5 data packets. -If the previous profile is understood as a "single challenge, single response" -where challenge (and also response) is sent as a burst of 5 data packets, -the new profile uses "bursts" of 1 packet instead, but issues -the challenge-response part 5 times sequentially -(waiting for receiving the response before sending next challenge). -This new profile happens to have the same overall packet count -(when no re-transmissions are needed). -Although it is possibly more taxing for TRex CPU, -the results are comparable to the old traffic profile. - -Ip4base tests -~~~~~~~~~~~~~ - -Contrary to stateless traffic profiles, we do not have a simple limit -that would guarantee TRex is able to send traffic at specified load. -For that reason, we have added tests where "nat44ed" is replaced by "ip4base". -Instead of NAT44ed processing, the tests set minimalistic IPv4 routes, -so that packets are forwarded in both inside-to-outside and outside-to-inside -directions. - -The packets arrive to server end of TRex with different source address&port -than in NAT44ed tests (no translation to outside values is done with ip4base), -but those are not specified in the stateful traffic profiles. -The server end (as always) uses the received address&port as destination -for outside-to-inside traffic. Therefore the same stateful traffic profile -works for both NAT44ed and ip4base test (of the same scale). - -The NAT44ed results are displayed together with corresponding ip4base results. -If they are similar, TRex is probably the bottleneck. -If NAT44ed result is visibly smaller, it describes the real VPP performance. |