dslreports logo
site
spacer

spacer
 
    All FAQs Site FAQ DSL FAQ Cable Tech About DSL Distance DSL Hurdles »»
spc

spacer




how-to block ads




2. Terminology

Provisioning occurs when a new modem is initiated/activated. Sometimes configuration issues can come up, and you'll hear tech support say, "We will "reprovision" the modem." Think of it as "resetting" your connection.

by PapaSmurf See Profile

CMTS stands for Cable Modem Terminating System. It enables access over the hybrid fiber coaxial network via a cable modem.

by PapaSmurf See Profile

An MLS is a multi-layer switch. It interconnects with other network elements at the edge of the network. Multiple CMTS will usually aggregate into a single MLS.

by PapaSmurf See Profile
last modified: 2002-03-19 16:29:52

A backbone router is an OSI layer 3 device that connects with other backbone routers to form the complete network backbone. Some backbone routers will connect to backbone routers of other providers (non Cox HSI) as well to "peer" the network. Connection to the internet is provided through a backbone router that interconnects to an Internet provider's network.

Feedback received on this FAQ entry:
  • backbone routers are those router whose atleast one interface is in the transit area(backbone area,area 0) ,there can be more than one backbone routers.

    2012-03-09 14:29:28



by PapaSmurf See Profile edited by redxii See Profile
last modified: 2002-03-19 19:16:28

Hybrid Fiber Coax is a way of delivering video, voice telephony, data, and other interactive services over coaxial and fiber optic cables.

An HFC network works consists of a headend office, distribution center, fiber nodes, and network interface units.

The headend office receives information such as television signals, Internet packets, and streaming media, then delivers them through a SONET ring to distibution centers. The distribution centers then send the signals to neighborhood fiber nodes, which convert the optical signals to electrical signals and redistributes them on coaxial cables to residents' homes where network interface units send the appropriate signals to the appropriate devices (i.e. television, computer, telelphone).

by redxii See Profile

The cable system is divided into nodes. In most cable systems, there is fiber optic cable running from the cable company to a large box somewhere in that node. Inside that box there is a media converter which converts the signal from optical (light)to RF (radio frequency).

by redxii See Profile

DOCSIS (Data Over Cable Service Interface Specification) is the Cable Modem standard that defines the interface requirements of high-speed data transmission over cable networks. You can also see the CableLabs Certified logo on some modems, which also means the modem is DOCSIS compliant.

by redxii See Profile

A cable modem is an electronic adapter that permits a personal computer to receive Internet data from the high-speed information resources of a cable television system. Cable modems permit personal computers to receive Internet information at rates of up to hundreds of times faster than typical, consumer market telephone modems. A cable modem attaches to a personal computer through a network interface card (NIC) installed inside the computer. The cable television system's cable brings the information into the cable modem and then the cable modem sends the information into the computer through the NIC.

by redxii See Profile

That's an excellent question. The reason is that both ping and traceroute use a special packet type called an Internet Control Message Protocol or ICMP packet. These are used primarily for network attached devices to send short messages to each other and as such are very different from transport protocols such as UDP or TCP, which is what 'real data' such as web pages or video downloads use.

As more computers moved from temporary connections such as dialup to permanent connections as we have today, it became common for virus and trojan writers to include a mechanism to search for nearby hosts via ping in an attempt to locate more systems to infect. The net sum of having to manage this additional flood of ICMP packets was that routers, firewalls and other network devices could become so busy responding to pings that they were rendered ineffective at actually sending real traffic...what is known as a denial of service attack.

This is why it is now common practice for engineers to setup their devices to treat ICMP with the lowest priority, if now downright ignore it (my Juniper firewall at home is set to ignore ICMP and thus can't be pinged) This is what is often called "de-prioritization" here and helps to ensure that 'real packets' get through before the fluff.

This is what you are seeing when you do a traceroute and one hop is showing loss or high latency while the next is just fine. You can tell it is just a case of the host in question taking its time to respond because if there was real packet loss that host would impact all the other hops because it sits between you and them.

and there it is in a nutshell, albeit a lengthy one

Explanation provided by bbeesley See Profile

by CoxTOC1 See Profile edited by PapaSmurf See Profile
last modified: 2009-01-07 15:22:10