Two big data center network standards lead to the division of the Network Industry

Although there are competitive standards and patent substitution standards in the marketIETFStill insist on saying,TRILLMulti-link transparent interconnection) as a solutionData CenterOne way to solve the problem of network Ethernet scalability is gaining momentum.

Indeed, the network industry seems to have deep differences in the best way. Some vendors support IETF TRILLProtocolSome vendors support the IEEE shortest path bridge SPB), some other vendors propose patent protocols, and some vendors advocate combining many methods.

TRILL is designed to overcome the limitations of the Ethernet Spanning Tree Protocol. The Spanning Tree Protocol is a method to prevent Network Loops and handle the backup path in the event of a fault. The Spanning Tree Protocol is inadequate because it does not use all available paths between switches and this path is not always the shortest or fastest. Therefore, topology clustering in the Spanning Tree Network is slow. This limits the network scalability and makes the network more prone to connection failures.

IETF attempts to address this defect in the trill rfc 5556 standard draft. TRILL is a layer-2 protocol that uses the link status routing image network to find and calculate the shortest path between the TRILL node named routing Bridge. This enables multi-hop routing in the shortest path. In this way, users can establish large-scale Ethernet and Ethernet fiber channel data center networks.

TRILL vs SPB: Who has more advantages?

Cisco, a leader in the Ethernet market, is introducing FabricPath technology for its Nexus 7000 switch. This technology can achieve TRILL to solve the same problem while providing more features. Cisco said FabricPath is the TRILL standard "Extension Set ".

Brocade) also said that its BrocadeOne structure is based on TRILL.

However, the just-released QFabric data center product line and the cloud architecture switch do not support the TRILL standard, but support a patented method for extending Ethernet in the data center.

Indeed, Juniper Networks is a public critic of TRILL standards. Pradeep Sindhu, founder and chief technology officer of zhanbo Network, said in the release of QFabric that TRILL is a solution to the problem and a method to expand the L2 network. However, most data center networks need to communicate on three layers. The Layer 3 is confined to a single-arm router and becomes a bottleneck. TRILL applies to data centers as a joke.

HP supports both TRILL and IEEE's competitive Technical Specifications SPB. SPB is an extension of the multi-Spanning Tree Protocol. The multi-Spanning Tree Protocol also uses a link status routing protocol, which allows the switch to understand the shortest path through an Ethernet structure and dynamically adjust it based on the structure changes.

Dominic Wilde, HP's chief technical expert and senior manager of the network department, said in an email to the online world that HP is actively researching TRILL-based solutions for traditional enterprise customer markets, this includes the open standards added to IETF. HP plans to release TRILL-compliant products in the second half of this year.

SPB is supported by more vendors

Wilde said HP will bridge the backbone network of the IEEE 802.11ah providerPBB) To SPB. PBB encapsulates the Mac address in the Mac address to upgrade the virtual LAN.

Wilde said that HP will continue to invest in PBB through the development of current standards such as SPB. SPB will provide scalability, multi-tenant service, elasticity, and multi-path between Edges and cores. Although these standards have begun to become solutions for service providers and carrier customers, they are more closely related to the enterprise environment of large-scale data centers.

Wilde said that HP is still using its intelligent elastic architecture IRF) network virtualization and cluster technology to expand the scalability and reliability of TRILL and SPB. Irf is designed to virtualize multiple physical IS-IS nodes into a single logical node to scale the data center structure. This will maintain a low skip count for efficiency and faster aggregation ).

Reg Wilcox, vice president of marketing and product management for Huawei fiber optic networks in North America, said that Huawei also supports SPB, it also points out that HP's favorite multi-tenant service and its maturity and operation management and maintenance capabilities are the reasons why Huawei supports this standard. Like HP, Huawei plans to expand and bridge the SPB and TRILL features.

Wilcox said that Huawei recognizes that neither IETF nor IEEE standards have all the functions that every user needs. We will work with other vendors to study these two standards to help users make up for these shortcomings at the lowest possible cost.

Considering the basis of its own carrier, Avaya and Alcatel-Lucent are applying SPB.

At the same time, Extreme recently announced that it will use a multi-system link aggregation M-LAG) as a method to replace Spanning Tree Protocol, SPB, and TRILL.

According to Extreme, TRILL and SPB both require major upgrades. Shehzad Merchant, Senior Strategy Manager of Extreme, said TRILL requires new packet encapsulation. Generally, most existing infrastructure does not support such data packets. It requires "Elimination and replacement ".

TRILL is more suitable for LAN architecture?

This is not the case, said Donald Eastlake, co-chair of the ietf trill Working Group. He said that the substantial benefits of TRILL certainly do not require "Elimination and replacement ". TRILL can be deployed step by step. "You can use TRILL switches or RBridges) to replace traditional bridging devices in sequence. However, if you use RBridges to replace more bridging devices in the LAN, you will gain more benefits from TRILL."

The M-LAG only supports a limited architecture, says Eastlake. In addition, the M-LAG may only have very limited multi-path capabilities and may still need to run the Spanning Tree Protocol in the event of a failure to ensure there is no problem.

The M-LAG says the proprietary alternative to Spanning Tree Protocols has been around for years. This evidence further shows that the Spanning Tree Protocol, which has been in the history of 1/4 century, lacks some things for some modern applications. In addition to proprietary technologies, this alternative method is generally only applicable to restricted structures. TRILL is applicable to common LAN structures.

For Avaya, SPB also works. Because of its simplicity and L2 focus, Avaya selects the data center switch that SPB uses for it.

Steve Bandrowczak, vice president of Avaya and general manager of Data Solutions, said flattening the network is part of our traditional operator. It is characterized by mitigating implementation and extending to the storage field. This is a correct path.

Avaya also believes that the SPBIEEE 802.1aq standard will be widely supported by the industry. However, Eastlake said that this technology only works in places that contain the nearest neighbor shortest path bridge and is limited to point-to-point connections.

According to Eastlake, IEEE has not yet fully determined this standard. Although 802.1aq IS still based on the IS-IS routing protocol, it must set a bridging mechanism for Frame Forwarding. Therefore, it cannot be routed, and its multi-path scalability is limited.

According to Eastlake, this is the reason why ECMP support for equivalent multi-path routing has been so limited and the computing overhead of each vswitch is much higher than that of TRILL, which causes its scalability to be lower than that of TRILL.

According to Eastlake, IEEE 802.1 is expecting a new plan to add routes to SPB and overcome these problems.

Select a shotgun or rifle?

Peter Ashwood-Smith, an author of SPB technology, said users have paid a price for scale control. He said one forwarding mode is like opening a shotgun, while another forwarding mode is like a rifle. TRILL Does shotgun shooting, while 802.11aq does rifle shooting. In our conversations with customers, we found that some people need scattered data packets, some people need more precise control, and most people need to select the two based on the communication type.

Ashwood-Smith said SPB also provides more predictability than TRILL. Its rifle-based forwarding method allows users to use offline tools to plan what will happen. Using shotgun Forwarding is more difficult and possibly impossible.

In addition, Ashwood-Smith said TRILL may require a wider range of device upgrades than SPB. To support shotgun forwarding, each card on each hop point must be upgraded, and the entry/exit card must be upgraded for SPB implementation. The 40/100G Ethernet Card can remain intact. Therefore, we believe that we can use Ethernet to provide users with low-cost solutions, at least in the short term.

As for computing, SPB provides an option, says Ashwood-Smith. In this option, you can disable the multicast status. This will make the computing speed significantly faster than TRILL. With regard to the standard progress, Ashwood-Smith said that the bankruptcy and asset sale of Nortel had frustrated SPB. The selection of shotgun Forwarding is added to this technical specification.

However, SPB of earlier versions of the standard has more than 20 practical applications and has carried out important interoperability tests, five physical switches and 32 analog switches from two vendors were tested in a laboratory of an enterprise in Ottawa. Ashwood-Smith expects SPB standards to be approved in the third quarter of this year.

At the same time, Eastlake said TRILL interoperability "plug-in Conference plugfest)" had been completed last year at the university interoperability lab in New York. Another meeting is under planning. TRILL's basic protocol IS a standard approved by IETF, the same as the two IS-IS guide documents. However, these guide documents have not yet published the RFC Internet standard draft ).

According to Eastlake, the TRILL Working Group has been re-authorized and further development of TRILL continues. These tasks include management, operation management, and maintenance. Cisco said its FabricPath technology is based on TRILL. BLADE Network Technologies acquired by IBM also supports TRILL. Therefore, Eastlake concluded that TRILL has an increasing momentum.