Ethernet access switch chip boosts service support
The Serval-2 architecture. Source: Vitesse
Vitesse Semiconductor has detailed its latest Carrier Ethernet access switch for mobile backhaul, cloud and enterprise services.
The Serval-2 chip broadens Vitesse's access switch offerings, adding 10 Gigabit Ethernet (GbE) ports while near-tripling the switching capacity to 32 Gigabit; the Serval-2 has 2x10 GbE and 12 1GbE ports.
The device features Vitesse's service aware architecture (ViSAA) that supports Carrier Ethernet 2.0 (CE 2.0). "We have built a hardware layer into the Ethernet itself which understands and can provision services," says Uday Mudoi, product marketing director at Vitesse.
CE 2.0, developed by the Metro Ethernet Forum (MEF), is designed to address evolving service requirements. First equipment supporting the technology was certified in January 2013. What CE 2.0 does not do is detail how services are implemented, says Mudoi. Such implementations are the work of the ITU, IETF and IEEE standard bodies with protocols such as Muti-Protocol Label Switching (MPLS)/ MPLS-Transport Profile (MPLS-TP) and provider bridging (Q-in-Q). "There is a full set of Carrier Ethernet networking protocols which comes on top of CE 2.0," says Mudoi.
Serval-2 switch
The Serval-2 switch features include 256 Ethernet virtual connections, hierarchical quality of service (QoS), provider bridging, and MPLS/ MPLS-TP.
An Ethernet Virtual Connection (EVC) is a logical representation of an Ethernet service, says Vitesse, a connection that an enterprise, data center or cell site uses to send traffic over the WAN.
Multiple EVCs can run on the same physical interface and can be point-to-point, point-to-multipoint, or multipoint-to-multipoint. Each EVC can have a bandwidth profile that specifies the committed information rate (CIR) and excess information rate (EIR) of the traffic transmitted to, or received from, the Ethernet service provider’s network.
The EVC also supports one or more classes of service and measurable QoS performance metrics. Such metrics include frame delay - latency - and frame loss to meet a particular application performance requirements.
The Serval-2 supports 256x8 class of service (CoS) EVCs, equivalent to over 4,000 bi-directional Ethernet services, says Mudoi.
The Serval-2 also supports per-EVC hierarchical queuing. It allows for 256 bi-directional EVCs with policing, statistics, and QoS guarantees for each CoS and EVC. Hierarchical QoS also enables a mix of any strict or byte-accurate weighting within the EVC, and supports the MEF's dual leaky bucket (DLB) algorithm that shapes traffic per-EVC and per-port.
"Service providers guarantee QoS to subscribers for the services that they buy," says Mudoi. "If each subscriber's traffic - even different applications per-subscriber - is treated using separate queues, then one subscriber's behavior does not impact the QoS of another." Supporting thousands of queues allows service providers to offer thousands of services, each with its own QoS.
Q-in-Q, defined in IEEE 802.1ad, allows for multiple VLAN headers - tags - to be inserted into a frame, says Mudoi, enabling service provider tags and customer tags.
Meanwhile, MPLS/ MPLS-TP direct data from one network node to the next based on shortest path labels rather than on long network addresses, thereby avoiding complex routing table look-ups. The labels identify virtual links between distant nodes rather than endpoints.
MPLS can encapsulate packets of various network protocols. Serval-2's MPLS-TP supports Label Edge Router (LER) with Ethernet pseudo-wires, Label Switch Router (LSR), and H-VPLS edge functions.
Q-in-Q in considered a basic networking function for enterprise and carrier networks, says Mudoi, while MPLS-TP is a more complex protocol.
Serval-2 also supports service activation and Vitesse's implementation of the IEEE 1588v2 timing standard, dubbed VeriTime.
"Before you provision a service, you need to run a test to make sure that once your service is provisioned, the user gets the required service level agreement," says Mudoi. Serval-2 supports the latest ITU-T Y.1564 service activation standard.
IEEE 1588v2 establishes accurate timing across a packet-based network and is used for such applications as mobile. The Serval-2 also benefits from Intellisec, Vitesse's MACsec Layer 2 security standard implementation (see Vitesse's Intellisec ).
"Both [Vitesse's VeriTime IEEE 1588v2 and Intellisec technologies] highly complement what we are doing in ViSAA," says Mudoi.
Availability
Serval-2 samples will be available in the third quarter of 2013. Vitesse expects it will take six months for system qualification such that Ethernet access devices using the chip and carrying live traffic are expected in the first half of 2014.
Transmode's evolving packet optical technology mix
- Transmode adds MPLS-TP, Carrier Ethernet 2.0 and OTN
- The three protocols make packet transport more mesh-like and service-aware
- The 'native' in Native Packet Optical 2.0 refers to native Ethernet
Transmode has enhanced its metro and regional network equipment to address the operators' need for more efficient and cost-effective packet transport.
“Native Packet Optical 2.0 extends what the infrastructure can do, with operators having the option to use MPLS-TP, Carrier Ethernet 2.0 and OTN, making the network much more service-aware”
Jon Baldry, Transmode
Three new technologies have been added to create what Transmode calls Native Packet Optical 2.0 (NPO2.0). Multiprotocol Label Switching - Transport Profile (MPLS-TP) was launched in June 2012 to which has now been added the Metro Ethernet Forum's (MEF) latest Carrier Ethernet 2.0 (CE2.0) standard. The company will also have line cards that support Optical Transport Network (OTN) functionality from April 2013.
Until several years ago operators had distinct layer 2 and layer 1 networks. “The first stage of the evolution was to collapse those two layers together,” says Jon Baldry, technical marketing director at Transmode. “NPO2.0 extends what the infrastructure can do, with operators having the option to use MPLS-TP, CE2.0 and OTN, making the network much more service-aware.”
By adopting the enhanced capabilities of NPO2.0, operators can use the same network for multiple services. “A ROADM based optical layer with native packet optical at the wavelength layer,” says Baldry. “That could be a switched video distribution network or a mobile backhaul network; doing many different things but all based on the same stuff.”
Transmode uses native Ethernet in the metro and OTN for efficient traffic aggregation. “We are using native Ethernet frames as the payload in the metro,” says Baldry. “A 10 Gig LAN PHY frame that is moved from node to node, once it is aggregated from Gigabit Ethernet to 10 Gig Ethernet; we are not doing Ethernet over SONET/SDH or Ethernet over OTN.”
Shown are the options as to how layer 2 services can be transported and interfaced to multiple core networks. The Ethernet muxponder supports MPLS-TP, native Ethernet and the option for OTN, all over a ROADM-based optical layer. “It is not just a case of interfacing to three core network types, we can be aware of what is going on in these networks and switch traffic between types,” says Transmode's Jon Baldry. Note: EXMP is the Ethernet muxponder. Source: Transmode.
Once the operator no longer needs to touch the Ethernet traffic, it is then wrapped in an OTN frame for aggregation and transport. This, says Baldry, means that unnecessary wrapping and unwrapping of OTN frames is avoided, with OTN being used only where needed.
There are economical advantages in adopting NPO2.0 for an operator delivering layer 2 services. There are also considerable operational advantages in terms of the way the network can be run using MPLS-TP, the service types offered with CE2.0, and how the metro network interworks with the core network, says Baldry.
MPLS-TP and Carrier Ethernet 2.0
Introducing MPLS-TP and the latest CE2.0 standard benefits transport and services in several ways, says Baldry.
MPLS-TP provides better traffic engineering as well as working practices similar to SONET/SDH that operators are familiar with. “MPLS-TP creates a transport-like way of dealing with Ethernet which is good for operators having to move from a layer-1-only world to a packet world,” says Baldry. MPLS-TP is also claimed to have a lower total cost of ownership compared to IP/MPLS when used in the metro.
The protocol is also more suited to the underlying infrastructure. “Quite a lot of the networks we are deploying have MPLS-TP running on top of a ROADM network, which is naturally mesh-like,” says Baldry.
In contrast Ethernet provides mainly point-to-point and ring-based network protection mechanisms; there is no support for mesh-based restoration. This resiliency option is supported by MPLS-TP with its support of mesh-styled ‘tunnelling’. A MPLS-TP tunnel creates a service layer path over which traffic is sent.
“You can build tunnels and restoration paths through a network in a way that is more suited to the underlying [ROADM-based] infrastructure, thereby adding resiliency when a fibre cut occurs,” says Baldry.
MPLS-TP also benefits service scalability. It is much easier to create a tunnel and its protection scheme and define the services at the end points than to create many individual circuits across the network, each time defining the route and the protection scheme.
“Because MPLS-TP is software-based, we can mix and match MPLS-TP and Ethernet on any port,” says Baldry. “You can use MPLS-TP as much or as little as you like over particular parts of the network.”
The second new technology, the MEF’s Carrier Ethernet 2.0, benefits services. The MEF has extended the range of services available, from three to eight with CE2.0, while improving class-of-service handling and management features.
Transmode says its equipment is CE2.0 compliant and suggests its systems will become CE2.0-certified in the new year.
Hardware
The packet-optical products of Transmode comprise the TM-Series transport platforms and Ethernet demarcation units.
The company's single and double slot cards - Ethernet muxponders – fit into the TM-Series transport platforms. The single-slot Ethernet muxponder has ten, 1 Gigabit Ethernet (GbE) and 2x10GbE interfaces while the double-slot card supports 22, 1GbE and 2x10GbE interfaces. Transmode also offers 10GbE only cards: the single slot is 4x10GbE and the double-slot has 8x10GbE interfaces. These cards are software upgradable to support MPLS-TP and the MEF’s CE2.0.
“In early 2013, we are introducing a couple of new cards – enhanced Ethernet muxponders – with more gutsy processors and optional hardware support for OTN on 10 Gigabit lines,” says Baldry.
The Ethernet demarcation unit, also known as a network interface device (NID), is a relatively small unit that resides for example at a cell site. The unit undertakes such tasks as defining an Ethernet service and performance monitoring. The box or rack mounted units have Gigabit Ethernet uplinks and interface to Transmode’s platforms.
Baldry cites the UK mobile operator, Virgin Media, which is using its platforms for mobile backhaul. Here, the Ethernet demarcation units reside at the cell sites, and at the first aggregation point the10- or 22-port GbE card is used. These Ethernet muxponder cards then feed 10GbE pipes to the 4- or 8-port 10GbE cards.
“For the first few thousand cell sites there are hundreds of these aggregation points,” says Baldry. “And those aggregation points go back to Virgin Media’s 50-odd main sites and it is at those points we put the 8x 10GbE cards.” Thus the traffic is backhauled from the edge of the network and aggregated before being handed over as a 10GbE circuit to Virgin Media’s various radio network controller (RNC) sites.
Transmode says that half of it customers use its existing native packet optical cards in their networks. Since MPLS-TP and CE2.0 are software options, these customers can embrace these features once they are required.
However, operators will only likely start deploying CE2.0-based services once Transmode’s offering becomes certified.
Further reading:
Detailed NPO2.0 application note, click here