Private Lines – How to interface to your network

June 7, 2011 by Leave a Comment

Surprisingly, there is very little written about interfacing a private line circuit to your network.  MPLS networks are not always the right solution for WAN connectivity.  For point-to-point networks, a private line or international private line could be the most cost effective solution.  But private lines typically do not come with routers and management.  This makes some people nervous about how they will make it work, but it shouldn’t be a real concern.

A Private Line is a TDM circuit, using Time Division Multiplexing to cost-effectively share your circuit with others on a carrier network.  To function, you need a CSU/DSU.

A CSU/DSU (Channel Service Unit/Data Service Unit, but no one calls it that!) is a digital-interface device used to connect a  router to a digital circuit (for example a T1, E1 p DS3 line).

A CSU/DSU operates at the physical layer (layer 1) of the OSI model.

So what does a CSU do? A CSU is acts as a buffer between a LAN and a public carrier’s WAN to ensure signals placed on the public lines are appropriately timed and formed for the network. The DSU manages timing errors and signal regeneration, providing a “modem-like” function , it converts digital data frames from the local area network (LAN) into frames appropriate to a wide-area network (WAN) and vice versa. The CSU receives and transmits signals from and to the WAN line and provides a barrier for electrical interference from either side of the unit. The CSU can also echo loopback signals from the phone company for testing purposes.

The CSU/DSU can be a separate piece of hardware mounted on the wall.  More commonly, it is simply a card that is part of a router.  The WIC (WAN Interface Card) may contain an integrated CSU/DSU that can be inserted into a router slot.

Once your Private Line has timing set up between the far and near ends, you then simply configure your router as you would for any other wide area network.

 

Filed Under: International Networks, International Private Leased Circuit - IPLC, Network FAQs, Private Lines Tagged With: , , , , , , ,

Powerful routers at bargain prices

July 20, 2009 by Leave a Comment

If you have an MPLS network, then you need solid routers. You may use Cisco, Juniper or Adtran.

Have you discovered open source and the Linux operating system? I don’t often tout a particular company, but routers are costly pieces of hardware and there are some new options that are worth exploring. Why? Because you can obtain far better functionality at a lower price.

Vyatta is a player in this space worth looking into. They provide fully supported software that runs on a Linux box to provide you with powerful router functionality. Using off the shelf x86 hardware, their software has proven to outperform Cisco in independent testing.

For example, using a 1-2 core processor, Cisco 2800 series performance for $1,000. Or how is Cisco ASA 5510 performance for $1,200?

Using a 3-4 core x86 processor, Cisco 3800 performance for $1,120. Or Cisco 7200 performance for $1,500.

And this is for a fully supported product that has a track record. LAN routing throughput has twice the performance at half the price. All, with 3x the route capacity at 1/4 the price.

If you are open to Linux, this is a company worth checking out.

Filed Under: Network FAQs, Quotation Thoughts, Routers Tagged With:

Making a router choice: Cisco 1841 or Cisco 2811

November 13, 2008 by Leave a Comment

When you are deciding on an MPLS network carrier, an important thing to consider is the router that will be provided, assuming that you want fully managed services.  This is a subject that many people are unclear on. 

Many carriers will provide a Cisco 1841 in their quotation.  The primary reason being cost.  Some carriers will quote a Cisco 2811.  While the cost is a bit higher, so in the expandability and performance.  While this blog is not intended to be a technical hardware discussion, the general subject of MPLS networks warrants a brief message about this topic.

Cisco 1841:

  1. List: $995 (depending on configuration)
  2. Memory (Std/Max): F: 32/128 and D:128/384
  3. LAN: 1 E/FE
  4. WAN Card Slots: 2 (data only)
  5. Network Module Slots: none
  6. Advanced Integration Module Slots: 1
  7. Digital Signal Processing Slots: none
  8. USB Ports: 1 (for USB Flash configuration)
  9. Form Factor: shelf
  10. Power supply redundancy: none
  11. Voice support: none
  12. Fast/CEF Switching: 38.40Mbps with 64 byte packets

Cisco 2811

  1. List: $1750 (depending on configuration)
  2. Memory (Std/Max): F: 64/256 and D:256/768
  3. LAN: 2 E/FE
  4. WAN Card Slots: 4 HWIC/VWIC/WIC/VIC (Hardware WAN Interface Card/Voice WIC/WIC/Voice Interface Card)
  5. Network Module Slots: 1
  6. Advanced Integration Module Slots: 2
  7. Digital Signal Processing Slots: 2
  8. USB Ports: 2 (for USB Flash configuration)
  9. Form Factor: rack
  10. Power supply redundancy: RPS-675 (optional power supply)
  11. Voice support: DSP/NM
  12. Maximum CCUE phones:  36
  13. Max SRST Phones: 36
  14. Fast/CEF Switching: 61.44 Mbps with 64 byte packets

To summarize:

  1. The 1841 is suitable for a single T1 or E1.  If you plan on using VoIP or growing to NxT1 or NxE1, select a better router.
  2. The 2811 is suitable for two T1s or E1s and supports voice.  It’s little brother the 2801 has less memory and less expansion slots, with a base configuration for a single T1 or E1.
  3. If your growth requirements will be greater, get the right router from the start to allow your upgrades to be painless and avoid any unexpected capital purchases.
  4. There are other router manufacturers than Cisco, so consider your options in full.
  5. Carrier provided routers and management will cost you more than leasing and managing the routers yourself, providing you have the resources to do it yourself.  Managed routers eliminate the management headache.
Filed Under: Notes About Implementations, Quotation Thoughts, Uncategorized Tagged With: , , , , , , ,

Reusing your routers on a new MPLS network

April 4, 2008 by Leave a Comment

When obtaining price quotations for new MPLS networks, intuition may tell you to reuse the routers that you may already have installed on your network.  What is common sense is not always true, if you want managed services.

Carriers provide managed services to remove the headache of network management (and add money to their bottom line).  Many carriers will only manage routers that they supply the customer.  This might seem unfair, but if they are managing thousands of routers around the world, it becomes “unmanageable” if they are managing dozens of different router and router configurations.  Their economy of scales require standardization.

On the other hand, if you have rather standard routers, such as Cisco 1841, 2811, 3222 then the use of these routers could be a negotiating point in getting the carrier to manage them.  Just be sure that you keep your Smartnet subscription up to date. But if your routers are old, start fresh.  Too much is riding on your network.

Filed Under: New MPLS Implementations, Notes About Implementations, Quotation Thoughts Tagged With: , , ,