computer science

Multiservice Switch

Multiservice Switch is a computer science topic covered in the lgStudy science library. This page brings together a partial reference excerpt, illustrations, worked examples, real-world applications and a short study plan, so you can understand Multiservice Switch rather than just read about it. In short: Multiservice Switch (MSS) is originally a Nortel line of routers, historically called Passport, designed for carrier core and edge routing. They run the Passport Carrier Release operating system.

Key takeaways

Multiservice Switch belongs to computer science; place it in that map before memorising details.
Learn the definition first, then one example that makes the definition concrete.
Connect Multiservice Switch to a quantity you can measure, compute or draw — that is where exam questions come from.
Reproduce the core statement of Multiservice Switch from memory before moving on to harder problems.

Reference excerpt

Multiservice Switch (MSS) is originally a Nortel line of routers, historically called Passport, designed for carrier core and edge routing. They run the Passport Carrier Release operating system. The MSS has a significant installed base, with over 40,000 switches sold. As of 27 September 2010, this product line was sold to Ericsson. The Nortel MSS products have been rebranded to Ericsson PPX.

Features Some core features of the Multiservice Switch series are:

MPLS with BGP VPNs RFC2764 VPNs SONET/ATM, Frame Relay and Ethernet Media Support IPv4 Routing (layer 3) Layer 3 Traffic Management

Architecture The Multiservice switches are made up of a shelf of 16 cards. There are two key types of cards to consider:

the Control Processor or CP is the switch fabric processor: it controls shelf functionality, as well as controls routing as well as manages the provisioning interface; the Function Processor or FP is in essence a line card, but there is processing logic and queue logic on the card. This allows for packets to be directly manipulated on the FP, decreasing the load on the CP. FPs normally process data frames on the ingress path and can autonomously forward frames to egress ports without further processing by protocol or control software on the egress FP. This is done by implementing backplane transfer, egress queuing and subsequent transmission all using ASICs. A shelf can have up to 2 CPs (1 master, 1 hot spare) and 14 FPs (including hot spares). The MSS has historically gone through two generations of Fabric Control Processors, starting with the i960 initially, and later moving to PowerPC. MSS software development started in 1990 before MSS hardware was available by applying paravirtualization techniques to VxWorks and running each CP or FP application payload on Sun SPARC workstations, each as a Unix user process.

Models The Multiservice Switch line is divided into several different models. This division is both historical and technical.

MSS 15000/20000 The top-of-the-line switch with a backplane capable of in excess of 50 Gbit/s of data transfer. This is the latest revision to the MSS line.

MSS 6400 One of the original Passport switches, the MSS 6400 has a significant historical installed base. Based on a redundant dual 800 Mbit/s backplane. The MSS 6400 had several different configurations available, the three slot 6420, the five slot 6440, and the 16 slot 6480.

MSS 7400 Initially running on the same hardware as the MSS 6400, the MSS 7400 uses Passport Carrier Release software only. The MSS 7400 range includes the three-slot 7420 (discontinued), the five-slot 7440, eight-slot 7460, and 16-slot 7480.

MSS 9400 The 16-slot MSS 9480 moves away from the dual shared 800 Mbit/s backplanes found in the 6400/7400 series of products. The 9480 backplane is switched, providing a dedicated dual bus to each line card. Most current 7400 line cards work in the 9480 chassis.

Supported media types There are a number of media types supported by the Multiservice Switch, both modern and historical. For example, Nortel offers line cards that provide Packet over SONET and ATM at OC3 through OC192 speeds (depending on the fabric capacity). As well, Frame Relay and other historical TDM interfaces can be purchased. More recently, Ethernet has become a focus for these switches, and 10/100/1000 media types have been supported (again depending on the fabric capacity).

Other uses The MSS chassis and architecture is an integral part of Nortel's CDMA and Alcatel-Lucent's (through acquisition) UMTS solutions. These switches run enhanced versions of Nortel's Passport Carrier Release software, but effectively are Multiservice Switches.

See also Nortel Passport Carrier Release

References

External links Multiservice Switch 6400 Multiservice Switch 7400 Multiservice Switch 15000/20000

Worked examples

Example 1 — a first encounter with Multiservice Switch

Start with the simplest possible case. Write down what Multiservice Switch claims or describes in one sentence, then invent the smallest concrete situation in which that sentence is true. In computer science, the smallest case is usually a single object, a single equation or a single measurement. Check that every symbol or term in your sentence has a meaning in that case.

Example 2 — changing one variable

Take the situation from Example 1 and change exactly one quantity: double it, halve it, or set it to zero. Predict what should happen to Multiservice Switch before you calculate. Comparing your prediction with the result is the fastest way to find out whether you understand the idea or only the words.

Example 3 — an exam-style question

Typical questions about Multiservice Switch ask you to (a) state it precisely, (b) apply it to given data, and (c) explain a limitation. Practise writing all three answers in under five minutes; the third part is what separates a full-mark answer from an average one.

Applications of Multiservice Switch

In research: Multiservice Switch appears in computer science research whenever the underlying quantities have to be modelled precisely. Papers usually cite it as a starting assumption and then explore where it breaks down.
In technology and industry: Engineering practice reuses Multiservice Switch in design rules, simulations and safety margins. Knowing the idea lets you read a specification sheet and understand why the numbers look the way they do.
In the classroom: Multiservice Switch is common in secondary-school and first-year university syllabi. It links to neighbouring topics Hardware routers, Networking hardware, Nortel products, so understanding it makes those chapters shorter.
In everyday life: Look for Multiservice Switch outside the textbook — in sport, cooking, traffic, electronics or the sky above you. An example you found yourself is remembered far longer than one you were given.

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How to study Multiservice Switch in 20 minutes

Read the reference excerpt below once, without taking notes.
Close the page and write down what Multiservice Switch means in your own words.
Compare your version with the excerpt and mark what you missed.
Work through the three examples above with pen and paper.
Explain Multiservice Switch out loud to somebody else — or to Teacher Smith in the lgStudy chat.

Frequently asked questions

What is Multiservice Switch in simple terms?

Multiservice Switch (MSS) is originally a Nortel line of routers, historically called Passport, designed for carrier core and edge routing. They run the Passport Carrier Release operating system.

Why does Multiservice Switch matter?

Because it connects several computer science ideas at once: it gives you a definition you can apply, a quantity you can calculate, and a way to check whether a result is plausible.

How should I study Multiservice Switch?

Read the excerpt, restate it from memory, then work through the examples and applications listed on this page. The five-step study plan above takes about twenty minutes.

What does this page cover?

It gives you a compact reference excerpt plus original lgStudy explanations, examples, applications and study material on Multiservice Switch.