User`s guide

Chapter XIII. Bypass Driver
Chelsio T5/T4 Unified Wire For Linux Page 186
1. Introduction
Chelsio’s B420 and B404 Bypass Adapters are Ethernet cards that provide bypass functionality
and an integrated L2, L3, and L4 Ethernet switch. The integrated switch allows for selective
bypass on a per-packet basis at line rate.
To use the bypass adapters, you must have both the Chelsio NIC driver and the bypass CLI
user space application loaded.
1.1. Features
B404 is a four-port 1G and B420 is a two-port 10G, short-range or long range, low profile PCI-
Express Host Bus Adapters (HBAs) using T4 ASIC.
Bypass
 Software programmable behavior on power fails – either Bypass Mode or Drop
Mode.
 Firmware control of Bypass / Normal / Drop Modes when T4 timer expires.
 Bypass control via software
 Drop Mode control by putting the associated PHY in reset.
Selective Bypass – Programmable HW traffic classification and redirection without host
intervention in normal mode
Product function:
The Bypass Adapters can operate in 4 modes.
 Bypass Mode
 Normal Mode
 Disconnect Mode
 Selective Bypass Mode
Bypass Mode
In this mode the Bypass adapter switches the packet from one port to another port. That is, in
B420, port 0 to port 1 and vice versa; and in B404, port 0 to port 1 and port 2 to port 3 and vice
versa.
Normal Mode
The Bypass Adapters can be programmed to function as a NIC. In this mode all the packets are
redirected to the host.