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Optical/IP

MPLS Arrives in Access Nets

One of the trends that’s likely to be evident at next week’s Supercomm tradeshow is the arrival of Multiprotocol Label Switching (MPLS) in access networks.

In essence, carriers have bought the idea of using MPLS in the core of their networks to enable them to consolidate services onto a single, converged backbone. Now, vendors are trying to push the multiservice edge outwards towards the customer, with the goal of making it easier for operators to manage the traffic on their networks and offer better quality-of-service guarantees, at the same time as making everything more scaleable.

In order to do this, vendors have got to bring down the cost of supporting MPLS in access equipment, and at least three vendors are unveiling developments this week that do just that:

World Wide Packets Inc.

World Wide Packets has announced two new MPLS access devices -- the LE-54v and the LE-311v. The LE-54v is the subscriber-side box with two 1-Gbit/s small form-factor pluggable (SFP) optical Ethernet ports and eight 10/100-Mbit/s subscriber ports. When one of the SFP ports is used as the network uplink, the second can be a subscriber interface (see WWP Couples Ethernet and MPLS).

The gear is new, but the ideas driving it aren't. Still, core MPLS equipment providers are warming up to adding an access piece to their story. Barry Kanter, WWP's VP of marketing, says the company is in discussions with every core MPLS switch vendor except Cisco about possible partnerships or reseller arrangements.

The LE-311v is the same box, but larger. It has four 1-Gbit/s SFP optical Ethernet ports and 24 10/100-Mbit/s subscriber ports in a one-rack-unit (RU) system. The LE-311v will be available at the end of July, but the LE-54v won't be around until September 30, the company says.

Both devices from WWP will initially provide transparent LAN Ethernet services, where customer traffic separation is handled via encapsulation or Ethernet virtual connections. When the time is right, the carrier can make a software change and -- on a port-by-port basis -- go from transparent LAN Ethernet mapping to PWE3 (psuedo-wire emulation) encapsulation, without rebooting the device. (For more on PW3, see Standardizing Ethernet Services, page 6.)

Mangrove Systems Inc.

Mangrove Systems Inc. was recently spotlighted for its marketing approach to Supercomm (see Startups Size Up Supercomm). It's going a slightly different route than WWP, with three new systems, including a central office aggregation box (see Ciena Previews Data Enchancements). Mangrove is offering:

  • Piranha 100 Access Multiplexer, a customer-located device;
  • Piranha 600 Access Concentrator, an aggregation system for large customer or central office installations; and
  • Barracuda Enhanced Services Shelf, an aggregation device for the central office that handles packet and circuit traffic from the access network. It's main purpose is to offload data traffic from crossconnects.
Each system uses PWE3 to send a mix of Ethernet, ATM, and Frame Relay services. That traffic is then encapsulated using GFP so it can be sent across the carrier's existing Sonet transport network.

This idea of sending many types of traffic through one pipe from the customer site to the carrier's central office should sound familiar. One of Mangrove founder Jonathan Reeves's previous companies -- Sahara Networks -- preached a similar story, but with ATM to the customer premises instead of MPLS. Reeves bootstrapped Mangrove in early 2002, then landed $3.1 million in early seed funding, including some of his own money.

Reeves had founded Sahara Networks in 1995, and the company was acquired by Cascade Communications about 18 months later. He founded Sirocco Systems in 1999, and it was acquired by Sycamore Networks Inc. (Nasdaq: SCMR) about 18 months later (see Sycamore Takes Over Sirocco and Reeves Seeds Mangrove Systems ).

Overture Networks Inc.

Overture Networks is offering access products designed to help carriers migrate to MPLS when ready. Using a variety of possible interfaces, Overture's ISG products make sure everything leaves the building as a packet, even TDM voice traffic (see Overture Raises $15M and Overture Launches Access Platform).

At Supercomm, the company says, it will unveil two more multiservice access boxes designed to help carriers offer Ethernet services to "any branch office or subscriber at any location."

Other examples of MPLS-based access equipment include the 3750 router from Cisco Systems Inc., the RS1000 and RS1100 from Riverstone Networks Inc. (OTC: RSTN.PK), and the Alcatel 7450 from Alcatel SA (NYSE: ALA; Paris: CGEP:PA), according to Geoff Bennett, chief technologist for Heavy Reading, who is writing of survey of equipment in the space (see Alcatel Pushes Ethernet-Over-MPLS ).

— Phil Harvey, News Editor, Light Reading

Tyler Durden 12/5/2012 | 1:34:58 AM
re: MPLS Arrives in Access Nets Can anyone discuss relative the merits (or demerits) of using MPLS in Access as opposed to L2 and L2 VPNs? (I've actually been a believer of MPLS in access for a quite a while, but I admit my reasons for favoring this approach may be out of date.)
ARBoy 12/5/2012 | 1:34:56 AM
re: MPLS Arrives in Access Nets And what makes these companies believe that they've got what it takes? What differentiates these unknown, untried, unproven vendors over the more established companies like Cisco and Juniper?

Sounds like more VC money about to make a loud, sucking sound.
arch_1 12/5/2012 | 1:34:53 AM
re: MPLS Arrives in Access Nets Just judging from the article, the new offerings appear use MPLS to provide logicaly separate "pipes" for each type of traffic from a customer to a PoP. This mechanism is useful for differentiated services. However, (and again, just judging from the article) the pipes terminate at the PoP. This is important for two reasons: 1) it only requires a relatively small number of pipes per subscriber in hte access boxes and 2) it only requires a relatively small number of pipes in the edge and core.

Given all this, there is no theoretical difference between pipes implemented as MPLS LSPs and pipes implemented as VLANs. There are practical differences, of course

VPNs are another story, because an L2 or MPLS VPN requires state in the core. If rhis type of VPN becomes pervasive, the core will need a massive amount of state information.
kampar 12/5/2012 | 1:34:48 AM
re: MPLS Arrives in Access Nets
I guess the point is that ...

1. PWE3 LSPs differ from VLANs in that they can carry multi-service traffic - not just your 'new' Ethernet services - there's a lot of TDM frame relay pipes you could convert to packets at the edge to save metro bandwidth (there was an article on LR about AT&T's presentation at a conference where they said this would be huge for them)

2. It's not just about access - setting up an MPLS PWE3 LSP to carry end-to-end multi-service traffic across the MPLS core network to 'emulate' the switched layer 2 services of today might enable carriers to get off their legacy ATM switch faster ... moving to the converged MPLS core (isn't that what the Martini drafts were supposed to make happen?)

I guess it may make sense to do this in the metro and access if you can do it cheaper just at layer 2 ... the price of these types of interfaces on Cisco and Juniper routers is pretty high (everyone complains about this) as they carry the cost of all the L3 services that may or may not be needed. It sounds like a parallel for the same issue that led to the explosion in the ATM IAD market - service interfaces on ATM switches were just too expensive and in the wrong place in the network.

Interesting that multiple companies seem to be coming to market with this at the same time, although WWP seems to be more of a future story and Ethernet focused.

Mixing PWE3 and GFP sounds different ... is there a standard for this?


netboarder 12/5/2012 | 1:34:45 AM
re: MPLS Arrives in Access Nets 1. PWE3 over GFP is not standardized yet (ITU G.7041 work is in progress). GFP User Payload Identifier (UPI, which denotes the type of payload encapsulated by the GFP layer) doesnGÇÖt include MPLS yet. So until ITU refreshes the GFP spec, an MPLS encapsulated packet (such as PWE3 packets) must have a mediation layer such as PPP, Ethernet, or RPR, which have a formal GFP UPI.

2. MPLS in the access networks, is okay as long as it stays point to point, at least up to the first Metro edge equipment. When considering multipoint services (l2vpn/VPLS), the requirement for a full mesh of pseudowires between PEs doesnGÇÖt scale well enough [n x (n-1) LSPs] to start from the customer location or the low-end access switch. H-VPLS approaches this problem by allowing either QinQ, or Hub & Spoke pseudowires to be used in the access, while the full mesh starts only higher in the network.

3. ItGÇÖs becoming quite obvious that MPLS L2 VPNs (aka VPLS) will dominate the metro network. In addition, pseudowires are becoming the transport (as is E1, FR, ATM, etc.). It makes good sense to push it out as close to the customer as possible but, as stated above, the multipoint solution should be an Hierarchical VPLS.

4. Another point to consider is where you want your routing to start. The l2vpn relieves most metro networks from the need to do IP routing, leaving it to the edge routers at the IP/MPLS edge (where the L3VPN startsGǪ).
opinion 12/5/2012 | 1:34:45 AM
re: MPLS Arrives in Access Nets MPLS is standardized, other access technologies aren't. Also reroute times have gotten in the SONET realm of <50ms.
materialgirl 12/5/2012 | 1:34:37 AM
re: MPLS Arrives in Access Nets Layer 2 service is cheap and fast, while Layer 3 is pricier, but more intelligent. The question seems to be how far into a network you can go with Layer 2 without running into management or traffic interference problems. Could you get the dreaded "broadcast storm" in a Layer 2 metro network?
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