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diff --git a/docs/development/design/traffic_desc.rst b/docs/development/design/traffic_desc.rst new file mode 100644 index 0000000..2a40b6a --- /dev/null +++ b/docs/development/design/traffic_desc.rst @@ -0,0 +1,85 @@ +.. This work is licensed under a Creative Commons Attribution 4.0 International +.. License. +.. http://creativecommons.org/licenses/by/4.0 +.. (c) Cisco Systems, Inc + +Traffic Description +=================== + +The general packet path model followed by NFVbench requires injecting traffic into an arbitrary +number of service chains, where each service chain is identified by 2 edge networks (left and right). +In the current multi-chaining model: + +- all service chains share the same left and right edge networks +- each port associated to the traffic generator is dedicated to send traffic to one edge network + +In an OpenStack deployment, this corresponds to all chains sharing the same 2 neutron networks. +If VLAN encapsulation is used, all traffic sent to a port will have the same VLAN id. + +Basic Packet Description +------------------------ + +The code to create the UDP packet is located in TRex.create_pkt() (nfvbench/traffic_gen/trex.py). + +NFVbench always generates UDP packets (even when doing L2 forwarding). +The final size of the frame containing each UDP packet will be based on the requested L2 frame size. +When taking into account the minimum payload size requirements from the traffic generator for +the latency streams, the minimum L2 frame size is 64 byte (no vlan tagging) or +68 bytes (with vlan tagging). + +Flows Specification +------------------- + +Mac Addresses +............. +The source MAC address is always the local port MAC address (for each port). +The destination MAC address is based on the configuration and can be: + +- the traffic generator peer port MAC address in the case of L2 loopback at the switch level + or when using a loopback cable +- the dest MAC as specified by the configuration file (EXT chain no ARP) +- the dest MAC as discovered by ARP (EXT chain) +- the VM MAC as dicovered from Neutron API (PVP, PVVP chains) + +NFVbench does not currently range on the MAC addresses. + +IP addresses +............ +The source IP address is fixed per chain. +The destination IP address is variable within a distinct range per chain. + +UDP ports +......... +The source and destination ports are fixed for all packets and can be set in the configuratoon +file (default is 53). + +Payload User Data +................. +The length of the user data is based on the requested L2 frame size and takes into account the +size of the L2 header - including the VLAN tag if applicable. + + +IMIX Support +------------ +In the case of IMIX, each direction is made of 4 streams: +- 1 latency stream +- 1 stream for each IMIX frame size + +The IMIX ratio is encoded into the number of consecutive packets sent by each stream in turn. + +Service Chains and Streams +-------------------------- +A stream identifies one "stream" of packets with same characteristics such as rate and destination address. +NFVbench will create 2 streams per service chain per direction: + +- 1 latency stream set to 1000pps +- 1 main traffic stream set to the requested Tx rate less the latency stream rate (1000pps) + +For example, a benchmark with 1 chain (fixed rate) will result in a total of 4 streams. +A benchmark with 20 chains will results in a total of 80 streams (fixed rate, it is more with IMIX). + +The overall flows are split equally between the number of chains by using the appropriate destination +MAC address. + +For example, in the case of 10 chains, 1M flows and fixed rate, there will be a total of 40 streams. +Each of the 20 non-latency stream will generate packets corresponding to 50,000 flows (unique src/dest address tuples). |