Products

Loop Bonding Technology

Loop bonding allows multiple physical lines to be grouped together in order to achieve higher data rates. For example, four 5.7Mbps SHDSL lines can be combined to provide 45Mbps of bandwidth. Loop bonding requires no extra configuration, and is an easy way to increase line speeds where extra copper is available. The most common standard for Ethernet loop bonding is the 802.3ah Ethernet in the First Mile (EFM) standard, which provides a robust and reliable bonding mechanism using SHDSL. Zhone also offers Ethernet bonding over T1, E1 and DS3 to provide more flexible deployment options.

Loop bonding technology is available for DSL and T1/E1 access technologies and can be achieved using EtherXtend or Network Extender products in point-to-point configurations, or in conjunction with the MALC Broadband Loop Carrier or IPD12000E IP DSLAM.

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Frequently Asked Questions

How many copper pairs do I need for loop bonding?

That depends on what type of connection you are applying loop bonding to. With SHDSL, each DSL line requires a copper pair (2 wires), so when bonding two SHDSL lines together, two pairs (4 wires) are required. However, when bonding T1/E1 lines, you can bond up to eight T1s or E1s between the same two locations. These T1/E1s may be backhauled over fiber, or may be dedicated 4-wire copper loops.

Will loop bonding extend the reach of SHDSL?

No, but it will increase the effective speed of an SHDSL link at any given distance. That is, in long reach applications (25,000+ feet/7,620+ meters) a single SHDSL line may only provide 272Kbps or even 144Kbps. With two bonded SHDSL lines, the same distance provides double the bandwidth, or 544Kbps and 288Kbps, respectively.

What happens if one line in a bonded group fails or is cut?

Unlike older bonding technologies like IMA or ML-PPP, Ethernet loop bonding is resilient. The addition or removal of a new copper pair into a bonded group will not impact other lines in that group. This creates a very stable and resilient bonded access connection.

What are the noise/crosstalk implications when running such high data rates over DSL?

Due to built in crosstalk cancelaltion features, and the spectrally friendly nature of SHDSL.bis, Ethernet bonded groups over SHDSL are very tolerant of noise.

Are Zhone's products 802.3ah compliant?

Yes. All new ZHone products including EtherXtend CPE and MALC EFM line cards support the IEEE 802.3ah EFM specification for 2Base-TL. Older EThernet over SHDSL products, including the IPD12000 and SHDSL Network Extender (SNE) products are not compliant; However, Zhone fully supports both modes of operation on all new products, ensuring full backwards compatibility with older products.