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MontaVista rev’s carrier grade distro for 4G

Oct 19, 2009 — by Eric Brown — from the LinuxDevices Archive — 3 views

MontaVista Software announced a new release of its Carrier Grade Linux (CGL) 4.0 compliant Linux distribution for networking customers, adding support for 4G wireless networks including LTE and WiMAX. MontaVista Linux Carrier Grade Edition (CGE) 5.1 also integrates OpenSAF High Availability (HA) capabilities and is the first to offer virtual routing and forwarding, says MontaVista.

Over 30 Linux Support Packages (LSP's) are available immediately for CGE 5.1, including LSPs for Intel x86, Freescale PowerPC, Cavium Octeon, and RMI XLR/XLS architectures, says MontaVista. According to the company, CGE is the most widely deployed CGL software in the world, with seven of the top eight networking equipment providers (NEPs) using the product. CGE is further claimed to have demonstrated "six-nines" (99.9999 percent) availability.

Like its predecessor, CGE 5.1 has been registered for compliance with the Carrier Grade Linux 4.0 spec at the Linux Foundation (LF). MontaVista remains only one of three vendors registered for the high end 4.0 networking spec, along with Performance Technologies (NexusWare) and arch rival Wind River. Meanwhile, MontaVista continues to claim to be the only carrier grade Linux distribution to be compliant with CGL 4.0, IPv6, and Linux Standards Base (LSB) 3.0 certifications.

With the release of the substantially reworked MontaVista Linux 6 (MVL6), last month, the mainstream version of MontaVista Linux has grown even more distinct from the networking focused CGE. The latter was last rev'd to version 5.0 in December 2007, when it added greater scalability, reliability, field-serviceability, security features, and a "flight recorder" for monitoring system crashes, said to be similar to an airplane's "black box."

According to VP of marketing Dan Cauchy in an interview on Friday, CGE is "a separate product" from MontaVista's mainstream MVL6. "MVL6 is more leading edge, and more focused on consumer electronics and mobile markets, whereas CGE 5.1 is based on an older 2.6.21 Linux kernel, because that's what our customers want," said Cauchy. "CGE offers ten years support and is intended to be very rock solid."

Cauchy (pictured), who is also chairman of the Linux Foundation's Carrier Grade Linux (CGL) working group, said that a CGL 5.0 spec will arrive next year. More comments from Cauchy on CGE 5.1 are filtered in below.

CGE goes 4G

4G wireless network support leads the way among major new features introduced in CGE 5.1. Specifically, CGE 5.1 adds support for SCTP (Stream Control Transmission Protocol), as well IPSEC with IKEv2 protocols, which are required by both the LTE and WiMAX standards. SCTP (also known as IETF rfc4960) is a robust, record-oriented transport layer, as opposed to the stream-oriented TCP. The protocol offers multi-homing and transparent failover functionality, by which endpoints of a connection can maintain more than one IP address, enabling transparent fail-over between redundant paths.

Among other benefits, SCTP enables NEPs to more easily integrate networking devices into multiple entry points on the core network, said Cauchy. "There has been progress on SCTP in the open source community, but the quality has been iffy," he added. "So we ported over 413 patches from various sources and thoroughly tested it. We believe we have the most stable SCTP implementation in the world."

The IKEv2 (Internet Key Exchange) security protocol (IETF rfc4301), meanwhile, is based on the Strong Swan IPSEC implementation of the Linux 2.6 kernel, says MontaVista. Strong Swan incorporates X.509 public key certificates, as well as optional secure storage of private keys on smartcards for secure authentication.

OpenSAF support

CGE 5.1 now supports the open source "OpenSAF" 3.0 high availability (HA) middleware implementation, which is consistent with Service Availability Forum (SAF) specifications. According to Cauchy, the product is, "as far as we know," the first full integration of OpenSAF in a commercial Linux distribution.

The OpenSAF project was launched in mid-2007, with the release of OpenSAF 1.0 code by Motorola's Embedded Communications Computing Group (ECC). Shortly after Motorola ECC was acquired by Emerson Network Power (ENP) in early 2008, ENP launched a formal OpenSAF Foundation to oversee the project, joined by Ericsson, HP, Nokia Siemens Networks, and Sun Microsystems. In addition to supporting select SAForum specs, the OpenSAF project is also aligned with the requirements of the Scope Alliance, which aims to promote the interoperability of COTS (commercial off-the-shelf) hardware and software for infrastructure equipment.

According to Cauchy, carriers and vendors have been talking a lot about OpenSAF, but no one has actually done much about it. "OpenSAF is geared as being an open solution, so networking software vendors with proprietary middleware solutions may not be see it as being in their best interest," said Cauchy. "But at the same time, vendors like Alcatel-Lucent and Cisco are interested in OpenSAF because they have over a decade of legacy code that they keep having to port to new platforms, and it's a huge burden. As they move to Linux, it's a double burden - they have to port it to a new platform and to Linux as well. With OpenSAF, however, all their HA middleware is included, so the porting burden is decreased considerably."

Virtual routing and forwarding, and DRBD

Cauchy is more confident in claiming CGE 5.1 as the first commercial Linux vendor to offer virtual routing and forwarding (VRF) capabilities. Implemented by MontaVista "from scratch," said Cauchy, VRF enables the use of more affordable COTS hardware for secure wireless networks.

"Carriers who use real-time operating systems like VxWorks already have VRF, so they wanted this on their Linux distributions as well," said Cauchy. "VRF allows the separation of routing and forwarding duties, so you can emulate three or four physical routers on a single multi-core blade, but still have separate IP. Among other benefits, this lets them sell services to smaller carriers using the same physical equipment."

Desite the name, the technology does not use a hypervisor, said Cauchy, but runs in native Linux, with networking stacks segregated into multiple virtual routing and forwarding tables. "Each is independent, so traffic is completely segregated, offering a high level of security," said Cauchy.

Finally, CGE 5.1 adds a much improved DRBD capability, based on the open source DRBD 8.0.14 software from Linbit. DRBD is said to offer RAID-like distributed storage redundancy across a network, replicating data despite the location, while handing lost packets, latency issues, and disk sync (see diagram below).

"DRBD is especially important for wireless networks where you have secure distribution," said Cauchy. "We have supported it before, but now we have enhanced it with new features like better packet loss handling."

DRBD architecture (Source: Linbit)
(Click to enlarge)

Other major preexisting CGE features include a run-time application patcher, which enables field engineers to apply a binary patch to a live system, and a "field-safe" application debugger, which debugs a live system without halting execution, says MontaVista. Additional features available in CGE 5.1 include multi-core and SMP support, a live application core dump capability, and the aforementioned "flight recorder" for tracking and logging system history. The distribution also supports the Transparent Inter-Process Communication (TIPC), used in clustered computer environments.

Real-time Linux features are said to include fast mutexes, threaded soft and hard IRQ handlers, and application-level priority inheritance and queuing. A "microstate accounting" feature, meanwhile, enables engineers to "accurately measure process and thread utilization on a CPU," says the company. As was the case previously, CGE 5.1 offers runtime components that integrate with its MontaVista DevRocket Eclipse-based IDE (integrated development environment) and toolsuite.

Stated Ravi Swaminathan, director of Software Ecosystem Alliances at Freescale Semiconductor, "MontaVista Linux CGE is a proven solution for design teams that need to adhere to the strict technical requirements of a carrier environment."

Stated YJ Kim, senior director, Networking and Communications Division, Cavium Networks, "MontaVista was the first carrier grade Linux to support the OCTEON Multi-core MIPS64 processors, which is imperative for our customers deploying 4G wireless networks. The new features in CGE 5.1, like virtual routing and forwarding, combined with OCTEON processors provide our joint customers with an optimized, market-leading performance, low power solution for service provider networking equipment."

Stated Alan Meyer, President of the OpenSAF Foundation. "As a recognized carrier grade Linux provider, MontaVista is helping to accelerate the adoption of OpenSAF as the next generation high-availability middleware solution for the carrier market."


MontaVista Linux Carrier Grade Edition (CGE) 5.1 is available now, with over 30 Linux Support Packages (LSPs) already available, says MontaVista. More information may be found here.

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