3.3.4. Impairment

Flows

Flows in E100 Chimera are identified using a flow ID (fid). Valid fids are 0-7, where fid = 0 is the port default flow.

When configuring the flow filters and flow impairments, the fid of the flow to be configured must be provided to the API using square brackets after the API command. E.g: PEF_INIT [fid].

Filters

A filter configuration can either be Basic (the default), or Extended. Basic mode enables configuration of a basic subset of protocol segments in a fixed order whereas Extended allows a much high degree of flexibility to filter within the first 128 bytes of a packet. The mode is selected with PEF_MODE. Basic mode allows filtering on:

  • Ethernet header

  • Up to two VLANs

  • Up to one MPLS label

  • The first IPv4 or IPv6 header

  • Up to six sequential bytes of payload anywhere within the first 128 bytes of the packet

  • Xena Test Payload IDs (TPID)

Extended mode allows filtering based on an initial Ethernet header followed by any combination of segments up to a total length of 128 bytes, as well as optionally Xena Test Payload IDs (TPID).

For example:

0/0 PEF_PROTOCOL [1,0] ETHERNET VLAN VLAN MPLS MPLS -4 ETHERNET VLAN`` could specify a Metro Ethernet Forum provider-tagged (first VLAN) customer-tagged (second VLAN) frame containing an MPLS tunnel (first MPLS label) containing an MPLS Pseudo Wire (second MPLS label + four bytes of Control Word) containing a single-tagged Ethernet frame.

Once the protocol layout has been specified it is possible to set up a sequence of value + mask bytes that selects the relevant fields of each protocol segment; see PEF_VALUE and PEF_MASK.

CLI for Impairment

CLI commands for impairment (E100 Chimera) functionalities: