IP Archives

31 07, 2011

IPv6 and PC Provisioning in a DOCSIS Network

Mia Colabrese2021-08-18T10:01:08-04:00July 31st, 2011|

With IPv6 on the way in a number of MSO (Multi-System Operator) networks, I have received numerous questions lately about how home devices such as routers and PCs attached to DOCSIS cable modems will get their IP addresses. Will cable operators suddenly start issuing IPv6 IP addresses to their customers? Will you as a subscriber need to upgrade your equipment to support IPv6? Or does the cable modem act as a Network Address Translation (NAT) device and hand-out IP address to each device attached to it? These are some very good questions and the answers are addressed in the DOCSIS specification as I will outline.

5 09, 2010

DOCSIS 3.0 Tutorial – DOCSIS Does IPv6

Mia Colabrese2021-11-24T09:23:28-05:00September 5th, 2010|

Everyone is familiar with Internet Protocol version 4 (IPv4) addresses. You probably even set them up in your home network, such as 192.168.1.1 IPv4 is described in IETF publication RFC 791 (September 1981), which replaced the previous version RFC 760, dating back to January 1980. So its safe to say that IPv4 has been around for some time and serving us quite well. New in DOCSIS 3.0 has support for IPv6. Why do we need this new version? IPv6 has a vastly larger address space than IPv4. This results from the use of a 128-bit address, whereas IPv4 uses only 32 bits. Believe it or not, major cable operators are running out IP address. This is due to more customers, not just for cable modems, but also for set top boxes and VoIP eMTAs. Further, deployed in cable networks are IP devices such as power supplies with embedded cable modems for monitoring voltage, temperature, current and more. All networks are getting more IP devices requiring more and more IP addresses, so the 2128 addresses allocated in IPv4 are no longer sufficient and we turn to the 3.4×1038 addresses provided in IPv6.

1 07, 2010

DOCSIS 3.0 Tutorial – The EQAM

Mia Colabrese2021-08-17T15:58:05-04:00July 1st, 2010|

In my article on DOCSIS 3.0 M-CMTS architecture, I talked about the distributed nature of the CMTS with an M-CMTS core (the CPU of the system), a DOCSIS Timing Server, and an edge Quadrature Amplitude Modulator (EQAM). I am going to cover the EQAM in detail in this article because in the past couple of years, EQAM (also spelled eQAM) has rapidly become part of our vocabulary but its operation and value often go unappreciated. Further, in order to fully understand DOCSIS 3.0 operation, downstream channel bonding, and possible issue which may arise, a thorough understanding of the eQAM is critical.

2 10, 2009

Speeding Upstream – Part I

Mia Colabrese2021-08-18T10:19:55-04:00October 2nd, 2009|

The first part of this article (in CT's March 2009 issue) discussed downstream potential issues, while this one focuses on the potential issues associated with upstream deployments. In particular, this article covers the critical upstream areas that one should be aware of when getting ready to deploy or already deploying DOCSIS 3.0.

16 02, 2009

Troubleshooting DOCSIS – VoIP Impairments > Delay & Jitter

Mia Colabrese2021-08-17T15:54:55-04:00February 16th, 2009|

In this blog I will address delay and jitter as they pertain to VoIP in a DOCSIS network. Delay, jitter and packet loss are the three primary impairment in a VoIP network, but packet loss was addressed in my Troubleshooting DOCSIS - VoIP Impairments > Packet Loss blog. After packet loss, delay is the second most disruptive impairment in VoIP networks. The effects of delay to the caller generally appear as echo and talker overlap. In PSTN communications, echo can arise as acoustic echo between the mouthpiece and

15 02, 2009

Troubleshooting DOCSIS – VoIP Impairments > Packet Loss

Mia Colabrese2021-08-17T15:45:30-04:00February 15th, 2009|

In this blog I am going to focus on VoIP packet loss, which is just one of the three (3) primary types of VoIP impairments that are present in a DOCSIS network. I will cover many RF and IP terms in this blog that I have not discussed in my previous tutorials, not to worry! This terminology is all fodder for future blogs. :-) To review, the three fundamental impairments which impact call quality of VoIP communications are as follows: * Packet Loss – The complete or partial loss of a packet containing actual voice payload. * Delay – The time a packet takes to traverse the space between the source and destination of a voice call. The space is comprised of both the physical distance the data must travel in addition to the active network routing and switching elements, which contribute additional delay. * Jitter – The variance of inter-packet arrival time from one transmitted packet to the next sequential packet.

9 02, 2009

DOCSIS and Cable Modems – How it works :: Cable Modem Registration

Mia Colabrese2021-08-17T09:54:53-04:00February 9th, 2009|

Through DOCSIS tutorial seminars, I have found the most effective way to bring someone up to speed on DOCSIS communications is by teaching the cable modem registration process. During the registration process, we will cover the RF physical layer, theDOCSIS Media Access Layer (MAC) and the Internet Protocol (IP) layer. Yes, the cable modem exercises the first three layers of the Open Systems Interconnection Reference Model (OSI Reference Model or OSI Model)...