Endace DAG 5.2X, User Manual

Page: 10 / 66

EDM01-33v1 DAG_7.5G4_Card_User_Guide
6 ©2008 Endace Technology Ltd. Confidential - Version 1 - November 2008
Extended Functions
Data Stream Management
The DAG 7.5G4 card supports the Data Stream Manager (DSM) feature. DSM allows you to
drop packets or route them to a particular receive stream based on the packet contents,
physical port and the output of two load balancing algorithms.
The DSM logic is implemented in firmware on the DAG 7.5G4 card and does not require
intervention from the host CPU once it is configured.
Note:
For detailed information on using the Data Stream Manager please refer to EDM04-
10 Data Stream Management API Programming Guide and EDM04-07 dsm-loader User
Guide available from the support section of the Endace website at
http://www.endace.com
Filter / Load Balancing Block
.
Packets are received from the line and stamped with an ERF header, then passed to the filter
and load balancing block. The filter block applies eight bit-mask filters simultaneously from
the start of the packet, producing a single true/false value for each filter (64 bytes).
The load balancing block applies two algorithms to the packet data, also producing one
true/false Boolean output per algorithm.
Lookup Table Block
The lookup table accepts the filter and load balancing outputs. It also receives the physical
port the packet arrived on and calculates a classification (also known as color) for the packet.
Colorizer and Drop Block
The color is then passed to the Colorizer And Drop (CAD) block to check if the packet should
be dropped. If not the color is inserted into the packet ERF record header and the packet
record is passed to the packet steering module.
Packet Steering Module
The Packet steering module looks at the color information contained in the record and
determines which receive stream the record should be routed to.
Inline Forwarding
The DAG 7.5G4 card supports inline forwarding which enables the card to receive and
transmit packets directly from a single memory. This allows you to forward packets from the
DAG card receive interface(s) to the DAG cards transmit interface(s) without the requirement
to copy them. Using inline forwarding you can receive, inspect, filter and forward packets
between ports.
dagfwddemo
which is a tool supplied with your DAG card demonstrates how you can apply a
user-defined BSD Packet Filter (BPF) to the traffic forwarded by the DAG card. Packets
which match the filter are forwarded, while packets that do not match are dropped.
For more detailed information on inline forwarding and using
dagfwddemo
please refer to the
EDM04-04 dagfwddemo User Guide available from the support section of the Endace website
at http://www.endace.com .