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Implementing LAN Bypass

Implementing LAN Bypass

LAN Bypass is used to prevent a failed, in-line networking appliance from blocking important network traffic. Failure could come at any level of software, hardware or power input within the device. It could be a temporary condition or more permanent in nature requiring a timely fix or reset. The key idea with the LAN Bypass feature is to ensure the continued flow of important network traffic, especially where blockage could result in lost revenue or that of critical data, as in an online transaction processing (OLTP) application where data may represent the company’s lifeblood.

LAN bypasses are simple devices that create a fault-tolerant link between a LAN and WAN port to enable the operation of the network in an open mode. Processing data by the appliance (which is now halted at any rate) is temporarily foregone in favor of the unimpeded flow of data across the network. 'Open mode' means that the security requirements of a particular application must be considered before including a LAN Bypass feature in order to weigh any security versus data value trade-off.

FIGURE 1. To configure a LAN bypass, two LAN ports are linked together during bypass mode operation in order to shunt network traffic around a faulted node and back to the network data-stream and onto the next inline device. Bypass is often a feature of the network node itself or it can be added to the network as a dedicated LAN bypass device.

When available, LAN bypass can take advantage of a network appliance's redundant power or UPS (uninterruptable power source) or be battery operated and designed to withstand a typical power outage. A LAN Bypass mirrors the nature of its networks by being either copper or fiber-based. They typically look like all the other RJ45 Ethernet LAN ports. Another important categorization is non-latching and latching bypass. A latching bypass is able to maintain its state with the power off; not so with non-latching bypass. This means the latching LAN bypass is not impacted by power failure, but the non-latching version will only be helpful where the appliance is able to maintain power through batteries or other back-up methods. 


FIGURE 2. IP-316A Expansion module with 2 SFP+ 10 GbE ports, Intel® 82599ES without latching bypass. Supports models: PL-80640, PL-10590.

The LAN Bypass feature is typically purchased as an option with the host appliance. The LAN Bypass feature can be located on-board an appliance's motherboard or, more commonly, gained through an optional add-on card connected to the motherboard. Depending on the card, additional features may be included, as well.  


FIGURE 3. PL-10610 with Intel Haswell EP processor demonstrates how a card can be added to an existing appliance to create a new product capable on LAN bypass. In this case, the IP-316A card (FIGURE 3) was added to a revised PL-10590 chassis to create the PL-1061A. The high performance device can be used for edge security with by-pass capability.


Below is a list of the WIN Enterprises LAN Bypass products that are available as add-ons to our appliances. Also included in the list are the appliances where LAN bypass is a standard feature. 





Add-on Cards for LAN Bypass

Model Number



Expansion module with 8 RJ45 GbE ports, Intel 82580EB with four pair Gen.3 bypass function. Support models: PL-10480, PL-80650, PL-80640, PL-10590


Expansion module with 2 SFP+ 10 GbE ports, Intel® 82599ES with latching bypass. Supports models: PL-10460, PL-80640, PL-10590


Expansion module with 2 SFP+ 10GbE ports, Intel® 82599ES with latching bypass


Expansion module with 8 RJ45 GbE ports with 2 pairs bypass, Intel® 82580EB. Supports model: PL-10480,


Expansion module with 4 SFP ports & 4 RJ45 GbE ports, Intel® 82580EB, two pair bypass (optional). Supports Models: PL-80310, PL-80470, PL-80660


Expansion module with 4 RJ45 GbE ports, Intel® 82574L or 82583V, bypass function (optional). Supports Models: PL-80310, PL-80470, PL-80500, PL-10530, PL-80610.


Expansion module with 4 RJ45 GbE ports, Intel® 82580EB, two pair bypass. Supports Models: PL-80310, PL-80470, PL-80660


Expansion module with 6 SFP ports & 2 RJ45 GbE ports, Intel 82580EB one pair bypass (optional). Supports Models: PL-80310, PL-80470,


Expansion module with 4 x RJ45 GbE ports, Intel I211AT, two pair bypass function(optional)--SBC #'s ???

Standard Platform Appliances that Support LAN Bypass


The PL-80730 supports nine GbE ports with bypass function base on Marvell® 88E1240/1310.


WIN Enterprises introduces the PL-80550, a fanless, small form factor as a general networking computer system. The unit features the Intel® Atom D2550 processor with either 4 or 6 GbE LAN ports with bypass function


2U Rackmount Appliance with Intel® 22nm Core i3/i5/i7 (formerly Haswell) Pentium® and Celeron® series, LGA1150 processors and Max 10x GbE ports, SATA, CF, Gen3 Bypass function


Platform has 7 GbE up to a max of 15 GbE ports via PCIe. To prevent network problems when the platform shuts down, PL-80310 supports two segments of LAN bypass function through WDT and GPIO pin definitions.

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