Under normal operational circumstances when the Steelhead appliance is fully operational, the LAN and WAN interfaces each have an Ethernet links negotiated towards the devices they it connected to: From the LAN interface to the LAN switch and from the WAN interface to the WAN router.
When an in-path interface goes in by-pass, due to the termination of the optimization service or when the appliance gets turned off, it will connect the cables of the LAN switch and the WAN router directly to each other and these two device should negotiate an Ethernet link together.
Ethernet link negotiation failure could happen when:
The cabling between the interfaces on the LAN switch and WAN router has become incompatible. Keep in mind that an in-path interface in by-pass mode acts like a crossover cable and that Fast Ethernet interfaces don't have the ability to detect the cable type. Also check the Cables section in the Installation Related Issues chapter.
The configuration of the interfaces on the LAN switch and the WAN router has become incompatible. For example, one WAN interface is setup to 100 Mbps Full Duplex and the LAN interface is set to auto-negotiation on gigabit speeds only, then there will never an Ethernet link established.
The in-path interface is by default configured for fail-to-wire
but can be configured to be fail-to-block. Use the commands
show interfaces inpath0_0 configured
to determine the current state and the configuration command
no interface inpath0_0 fail-to-bypass enable
to go to fail-to-block.
Figure 7.1. In-path interface being configured for fail-to-block
SH (config) # show interfaces inpath0_0 configured Interface inpath0_0 configuration Enabled: no DHCP: no Dynamic DNS DHCP: no IP address: 10.0.1.6 Netmask: 255.255.255.0 MTU: 1500 Failure mode: Bypass SH (config) # no interface inpath0_0 fail-to-bypass enable SH (config) # show interfaces inpath0_0 configured Interface inpath0_0 configuration Enabled: no DHCP: no Dynamic DNS DHCP: no IP address: 10.0.1.6 Netmask: 255.255.255.0 MTU: 1500 Failure mode: Disconnect