High fives: 5 Terabit OTN switching and 500 Gig super-channels.

Infinera has announced a core network platform that combines Optical Transport Network (OTN) switching with dense wavelength division multiplexing (DWDM) transport. "We are looking at a system that integrates two layers of the network," says Mike Capuano, vice president of corporate marketing at Infinera. 

"This is 100Tbps of non-blocking switching, all functioning as one system. You just can't do that with merchant silicon."

Mike Capuano, Infinera 

The DTN-X platform is based on Infinera's third-generation photonic integrated circuit (PIC) that supports five, 100Gbps coherent channels. 

Each DTN-X platform can deliver 5 Terabits-per-second (Tbps) of non-blocking OTN switching using an Infinera-designed ASIC. Ten DTN-X platforms can be combined to scale the OTN switching and transport capacity to 50Tbps currently.

Infinera also plans to add Multiprotocol Label Switching (MPLS) to turn the DTN-X into a hybrid OTN/ MPLS switch. With the next upgrades to the PIC and the switching, the ten DTN-X platforms will scale to 100Tbps optical transport and 100Tbps OTN and MPLS switching capacity.

The platform is being promoted by Infinera as a way for operators to tackle network traffic growth and support developments such as cloud computing where applications and content increasingly reside in the network. "What that means [for cloud-based services to work] is a network with huge capacity and very low latency," says Capuano.

Platform details

The 5x100Gbps PIC supports what Infinera calls a 500Gbps 'super-channel'. Each super-channel is a multi-carrier implementation comprising five, 100Gbps wavelengths. Combined with OTN, the 500Gbps super-channel can be filled with 1, 10, 40 and 100 Gigabit streams (SONET/SDH, Ethernet, video etc). Moreover, there is no spectral efficiency penalty: the super-channel uses 250GHz of fibre spectrum, provisioning five 50GHz-wide, 100Gbps wavelengths at a time.

"We have seen 40 and 100Gbps come on the market and they are definitely helping with fibre capacity issues," says Capuano. "But they are more expensive from a cost-per-bit perspective than 10Gbps." By introducing the 500Gbps PIC, Infinera says it is reducing the cost-per-bit performance of high speed optical transport.

DTN-X: shown are 5 line and tributary cards top and bottom with switching cards in the centre of the chassis. Source: Infinera

Integrating OTN switching within the platform results in the lowest cost solution and is more efficient when compared to multiplexed transponders (muxponder) configured manually, or an external OTN switch which must be optically connected to the transport platform. 

The DTN-X also employs Generalised MPLS (GMPS) software. "GMPLS makes it easy to deploy networks and services with point-and-click provisioning," says Capuano.

Each DTX-N line card supports a 500Gbps PIC but the chassis backplane is specified at 1Tbps, ready for Infinera's next-generation 10x100Gbps PIC that will upgrade the DTN-X to a 10Tbps system. "We have already presented our test results for our 1Tbps PIC back in March," says Capuano. The fourth-generation PIC, estimated around 2014 (based on a company slide although Infinera has made no public comment), will support a 1Tbps super-channel.

Adding MPLS will add the transport capability of the protocol to the DTN-X. "You will have MPLS transport, OTN switching and DWDM all in one platform," says Capuano.

OTN switching is the priority of the tier-one operators to carry and process their SONET/SDH traffic; adding MPLS will enable extra traffic processing capabilities to the system, he says.

Infinera says that by eventually integrating MPLS switching into the optical transport network, operators will be able to bypass expensive router ports and simplify their network operation. 

Performance

Infinera says that the DTX-N 5Tbps performance does not dip however the system is configured: whether solely as a switch (all line card slots filled with tributary modules), mixed DWDM/ switching (half DWDM/ half tributaries, for example) or solely as a DWDM platform. Depending on the cards in the DTN-X platform, the transport/ switching configuration can be varied but the 5Tbps I/O capacity is retained. Infinera says other switches on the market do lose I/O capacity as the interface mix is varied. 

Overall, Infinera claims the platform requires half the power of competing solutions and takes up a third less space.

The DTN-X will be available in the first half of 2012.

Analysis

Gazettabyte asked several market research firms about the significance of the DTN-X announcement and the importance of combining OTN, DWDM and soon MPLS within one platform.

Ovum 

Ron Kline, principal analyst, and Dana Cooperson, vice president, of the network infrastructure practice

"MPLS switching is setting up a very interesting competitive dynamic among vendors"

Dana Cooperson, Ovum

The DTN-X is a platform for the largest service providers and their largest sites, says Ovum. 

It sees the DTN-X in the same light as other integrated OTN/ WDM platforms such as Huawei's OSN 8800, Nokia Siemens Networks' hiT 7100, Alcatel-Lucent's 1830 PSS and Tellabs' 7100 OTS. 

"It fits the mold for Verizon's long-haul optical transport platform (LH OTP), especially once MPLS is added," says Kline. "NSN is also claiming it will add MPLS to the 7100. Once MPLS is added, then you have the big packet optical transport box that Verizon wants."

The DTN-X platform will boost the business case for 100 Gig in a similar way to how Infinera's current PIC has done at 10 Gig. "The others will be forced to lower price," says Kline.

Having GMPLS is important, especially if there is a need to do dynamic bandwidth allocation, however it is customer-dependent. "When you start digging, it's hard to find large-scale implementations of GMPLS," says Kline.

The Ovum analysts stress that the need for OTN in the core depends on the customer. Content service providers like Google couldn't care less about OTN. "It's really an issue for multi-service providers like BT and AT&T," says Cooperson, 

There is a consensus about the need for MPLS in the core. "Different service providers are likely to take different approaches — some might prefer an integrated box and others might not, it depends on their business," she says. "I think MPLS switching is setting up a very interesting competitive dynamic among vendors that focus on IP/MPLS, those that focus on optical, and those that are trying to do both [optical and IP/MPLS]. 

Ovum highlights several aspects regarding the DTN-X's claimed performance.

"Assuming it performs as advertised, this should finally give Infinera what it needs to be of real interest to the tier-ones," says Cooperson. "The message of scalability, simplicity, efficiency, and profitability is just what service providers want to hear." 

Cooperson also highlights Infinera's approach to optical-electrical-optical conversion and the benefit this could deliver at line speeds greater than 100Gbps. 

At present ROADMs are being upgraded to support flexible spectrum channel configurations, also known as gridless. This is to enable future line speeds that will use more spectrum than current 50GHz DWDM channels. Operators want ROADMs that support flexible spectrum requirements but managing the network to support these variable width channels is still to resolved. 

"It fits the mold for Verizon's long-haul optical transport platform (LH OTP), especially once MPLS is added"

Ron Kline, Ovum

Infinera's approach is based on conversion to the electrical domain when dropping and regenerating wavelengths such that the issue of flexible channels does not arise or is at least forestalled. This, says Cooperson, could be Infinera's biggest point of differentiation.

"What impresses me is the 500Gbps super-channel using five, 100Gbps carriers and the size of the switch fabric," adds Kline. The 5Tbps switching performance also exceeds that of everyone else: "Alcatel-Lucent is closest with 4Tbps but most range from 1-3Tbps and top out at 3Tbps." 

The ease of use is also a big deal. Infinera did very well in marketing rapid turn up: 10 Gig in 10 days for example, says Kline: "It looks like they will be able to do the same here with 100 Gig." 

Infonetics Research

 Andrew Schmitt, directing analyst, optical

"GMPLS isn't that important, yet."

The DTN-X is a WDM platform which optionally includes a switch fabric for carriers that want it integrated with the transport equipment, says Schmitt. Once MPLS is added, it has the potential to be a full-blown packet-optical system.

"[The announcement is] pretty significant though not unexpected," says Schmitt. "I think the key question is what it costs, and whether the 500G PIC translates into compelling savings."

Having MPLS support is important for some carriers such as XO Communications and Google but not for others. 

Schmitt also says GMPLS isn't that important, yet. "Infinera's implementation of regen-rich networks should make their GMPLS implementation workable," he says. "It has been building networks like that for a while."

OTN in the core is still an open debate but any carrier that doesn't have the luxury of a homogenous data network needs it, he says

Schmitt has yet to speak with carriers who have used the DTN-X: "I can't comment on claimed performance but like I said, cost is important."

ACG Research 

Eve Griliches, managing partner 

"Infinera has already introduced the 500G PIC, but the OTN is significant in that it can be used as a standalone OTN switch, and it has the largest capacity out there today"

The DTN-X as an OTN/ WDM platform awaiting label switch router (LSR) functionality, says Griliches: "With the LSR functionality it will be able to do statistical multiplexing for direct router connections."

Infinera has already introduced the 500 Gig PIC but the OTN is significant in that it can be used as a standalone OTN switch, and it has the largest capacity out there today. An OTN survey conducted last year by ACG Research found that the switch capacity sweet spot is between 4 and 8Tbps.

Griliches says that LSR-based products are taking time to incorporate WDM and OTN technologies, while it is unclear when the DTN-X will support MPLS to add LSR capabilities. The race is on as to whom can integrate everything first, but DWDM and OTN before MPLS is the right direction for most tier-one operators, she says. 

Infinera has over eight thousand of its existing DTNs deployed at 85 customers in 50 countries. The scale of the DTN-X will likely broaden Infinera's customer base to include tier-one operators, says Griliches.

ACG Research has heard positive feedback from operators it has spoken to. One stressed that the decreased port count due to the larger OTN cross-connect significantly improves efficiencies. Another operator said it would pick Infinera and said the beta version of the 500Gbps PIC is "working beautifully".