Re: what is dark fiber?
Good definition. Also buildings with fiber and electronics attached are referred to as "lit" buildings. For example I can say that my company has 200 "lit" buildings in the Portland metro area meaning we have fiber AND electronics in those buildings. Most LEC's or CLEC's don't provide dark fiber any more. Not enough money in it. -Bart KurekSales EngineerElectric Lightwave Inc. (ELIX)http://www.eli.netmailto:[EMAIL PROTECTED] - Original Message - From: Martin-Guy Richard To: [EMAIL PROTECTED] Sent: Tuesday, September 05, 2000 10:06 AM Subject: Re: what is dark fiber? Hi, Dark fiber Dark fiber is optical fiber infrastructure (cabling and repeater) that is currently in place but is not being used. Optical fiber conveys information in the form of light pulses so the "dark" means no light pulses are being sent. Dark fiber can refer to infrastructure that is in place but not yet ready to use. For example, some electric utilities have installed optical fiber cable where they already have power lines installed in the expectation that they can lease the infrastructure to telephone or cable TV companies or use it to interconnect their own offices. To the extent that these installations are unused, they are described as dark. "Dark fiber service" is service provided by local exchange carriers (local exchange carrier) for the maintenance of optical fiber transmission capacity between customer locations in which the light for the fiber is provided by the customer rather than the LEC. I took that definition on www.whatis.com: http://www.whatis.com/WhatIs_Definition_Page/0,4152,211891,00.html bahadir korkmaz wrote: hi. what is dark fiber? i found some sites that says dark fiber means unused fiber. is it so? i think dark fiber must be different then unused fiber. i mean for example. 10gigabit ethernet runs on dark fiber. dark must be something related to bandwidth or wavelength. if someone knows dark fiber definition i ll be happy. _ Get Your Private, Free E-mail from MSN Hotmail at http://www.hotmail.com. Share information about yourself, create your own public profile at http://profiles.msn.com. ___ UPDATED Posting Guidelines: http://www.groupstudy.com/list/guide.html FAQ, list archives, and subscription info: http://www.groupstudy.com Report misconduct and Nondisclosure violations to [EMAIL PROTECTED]
Re: calling all telco experts....framed/unframed mode
How much bandwidth are you actually looking for? A full E1 of capacity is going to be fairly expensive going from the US to the UK. How much actual CIR and burst are you looking to get? -Bart Kurek Sales Engineer Electric Lightwave Inc. (ELIX) http://www.eli.net mailto:[EMAIL PROTECTED] - Original Message - From: "Steve DAvies" [EMAIL PROTECTED] To: [EMAIL PROTECTED] Sent: Tuesday, September 05, 2000 10:36 AM Subject: calling all telco expertsframed/unframed mode Hi, We have a telco in the states who are offering us 2048 (E1) capacity link by muxing 2 T1's, this is being presented to us on V.35 (US end). In the UK it is being presented to us on X.21 They say this is possible, not being big on telco stuff I can do nothing but wait and see. They say that at the UK end the service is framed and at the US end it is unframed, and they are asking us if we can configure our router(s) to accomodate this. After much searching on the Cisco website we can only find info on configuring G.703/704 interfaces for framed/unframed mode using timeslot command: http://www.cisco.com/univercd/cc/td/doc/product/software/ios120/12cgcr/inter _c/icserint.htm#14633 So my question is, does anyone know what our telco is upto? Has anyone heard of this? Can we configure either our 7200 or 2600 to accomodate this request? Thanks in advance Steve Steve _ Get Your Private, Free E-mail from MSN Hotmail at http://www.hotmail.com. Share information about yourself, create your own public profile at http://profiles.msn.com. ___ UPDATED Posting Guidelines: http://www.groupstudy.com/list/guide.html FAQ, list archives, and subscription info: http://www.groupstudy.com Report misconduct and Nondisclosure violations to [EMAIL PROTECTED] ___ UPDATED Posting Guidelines: http://www.groupstudy.com/list/guide.html FAQ, list archives, and subscription info: http://www.groupstudy.com Report misconduct and Nondisclosure violations to [EMAIL PROTECTED]
Re: NORTEL TIPS
What kind of equipment are you needing assistance with? -Bart Kurek Sales Engineer Electric Lightwave Inc. (ELIX) http://www.eli.net mailto:[EMAIL PROTECTED] - Original Message - From: "Bogdan Popescu" [EMAIL PROTECTED] To: [EMAIL PROTECTED] Sent: Thursday, August 31, 2000 8:43 PM Subject: NORTEL TIPS Hi all, Somebody, posted NORTEL FIELD TECH. TIPS last year on this site. If someone remember the url for it or has some doc. please feel free and email them to me. Any help it will be much apreciatte. B. Get free email and a permanent address at http://www.netaddress.com/?N=1 ___ UPDATED Posting Guidelines: http://www.groupstudy.com/list/guide.html FAQ, list archives, and subscription info: http://www.groupstudy.com Report misconduct and Nondisclosure violations to [EMAIL PROTECTED] ___ UPDATED Posting Guidelines: http://www.groupstudy.com/list/guide.html FAQ, list archives, and subscription info: http://www.groupstudy.com Report misconduct and Nondisclosure violations to [EMAIL PROTECTED]
Re: ATM Dead?
I can give some first hand knowledge being in the industry of ATM sales. We haven't sold ATM in Portland metro for quite some time. Not because it is dead or because it is not functional but simply because it's to difficult for the average broadband consumer to understand. On paper it's simple. It's the implementation, maintenance and tuning they find difficult to understand. To overcome this ignorance and lack of willing we sell a product called TLS (Transparent LAN Service.) This is essentially ATM handed off to a device which converts to 10/100 Ethernet. Even this is getting harder to sell as we move to an IP centric environment and customer's generally need simple Internet access or a clear channel pipe. You'll still find ATM in bigger shops who have had ATM for some time now and have found that it suites their needs or have simply invested so much capital in hardware that it wouldn't make sense for them to move away. With QoS being quickly developed for Internet based applications most customer's find that these new devices will suite their needs. This is just my opinion. ;) -Bart Kurek Sales Engineer Electric Lightwave Inc. (ELIX) http://www.eli.net mailto:[EMAIL PROTECTED] - Original Message - From: [EMAIL PROTECTED] To: [EMAIL PROTECTED] Sent: Wednesday, August 30, 2000 7:31 AM Subject: RE: ATM Dead? Hi Group, I think labelling the ATM technology as dead would be an "overkill". ATM has its advantages as well as disadvantages. Mere opinions don't change facts. Following are some facts about ATM: ATM has evolved as a stable connection oriented transport that currently operates, ATM switch to ATM switch at up to OC-48 line rates. It also lends itself ably to traffic engineering (prior to MPLS it was the only technology that offered traffic engineering features). It delivers many advanced features such as PVC creation from any ingress to any egress in a given ATM backbone, sophisticated ( but complicated ) signaling to simplify path creation and re-routing around failures, and QoS features for bandwidth reservation, constant bit rate, variable bit rate, and unspecified bit rate services, applied to the cell. However, with these advantages, ATM also has certain drawbacks. The first and foremost being that of "overhead". ATM consumes nearly 10% of available bandwidth with a 5 byte cell header for each 48 byte payload cell, plus an additional 5% is needed for the adaption layer for IP over ATM as per RFC 1483. For example, an ATM OC-48 link requires 494Mbit/sec for overhead. Compounding the bandwidth issues is ATM's limited scalability at higher link rates. ATM switches have only recently delivered OC-48 interface rates and it is questionable whether OC-192 is feasible considering the overhead associated with segmentation and reassembly, wasted bandwidth, and other inefficiencies of pushing 53bytes across 10Gbit/sec links. Today the fastest IP router ATM interface is OC-12, which creates a bottleneck with the advent of OC-192 capable transport systems. When ATM is used as the transport for delivering IP in the Internet core we face a different set of issues. ATM requires its own administrative domain distinct from IP at Layer 3. The ATM network elements must be interconnected in such a way to provide redundancy. The entire ATM topology is transparent to the IP Layer 3 topology. Therefore a second topology at Layer 3 must be overlaid atop the ATM fabric. This is achieved by establishing PVC's between layer 3 routers. This creates another set of problems: 1. Two separate modalities are required for element management adding complexity and cost to network management. 2. IP route exchange with an IGP requires direct peering/adjacency with all neighbors, therefore the number of PVC's required grow by a factor of n-to-the-power-2; where n is the number of internal IGP routers. For example, for 300 routers: 44,850 PVC's would be necessary to establish a complete mesh. If 4 more routers are added the PVC count jumps to 46,056 (an increase of 1206 PVC's). This represents a substantial network-provisioning problem. In the event of a router failure in this scenario, the surviving routers will issue IGP routing updates on the order of n-to-the-power-3 (300 routers would issue 27 Million updates). This effect can be reduced by configuring route-reflectors/confederations, however, it still adds to the complexity and becomes a provisioning nightmare. 3. ATM uses its own signaling protocol (PNNI) to establish PVC's. IP uses OSPF, IS-IS, and BGP as its signaling protocols. The two signaling layers operate independently and therefore complicate interworking between the layers. To gain advantage of ATM traffic engineering features IP signaling protocols must run within the ATM PVCs. The question boils down to Howard's C. Berkowitz's often-quoted saying, "What is the problem that you are trying to solve ? Knowing the adva
