"E1 Line" and "V.35 interface" and "Point2point lease line"

[Kuldeep singh]

Hi Experts,

                 There are some basic queries related to E1, V.35, FastEthernet and Poin2point LL given below=>

1. Can we use E1 link for internet access or Point to Point lease circuit or Both ?

2. E1 link uses which serial standard V.35 or Else ? i m asking bcoz i have seen many articles where mentioned that

    E1 limit is 2.048 mbps but other Serial Port like v.35, X.21 or etc support upto 8 mbps ?

3. I saw many times somewhere Serial port configured with "Controller" command with ip address and somewhere only with ip address ???

Explain both cases ??

4. Suppose i have two locations and i want to do point to point connectivity, one location router have FastEthernet Port and

    other location router have Serial port, then is it possible ??

5. How to determine that how much Bandwidth required for Point to point Connectivity , suppose distance between

    two locations is 300 Kms then how much mbps circuit need to buy  (not for internet access only for Point to Point Connectivity)  ??

Note:=>  If you are fully confident about all of this then reply me otherwise plz ignore

[Giuseppe Larosa]

Hello Kuldeep,

wide questions indeed

1)  E1 provides a data connection that can be used for internet access or as a leased line.

An E1 is made of 32 timeslots that can be partitioned creating more then one logical serial interface that can have different uses but bandwidth is divided in multiples of 64 kbps.

2) E1 uses G.703 standard  that is based on two coaxial cables or it can be placed over an RJ-45 cable, conversion between G.703 and V.35 is provided by DCE3 modems.  E1 is based on TDM time division multiplexing and it includes 32 timeslots each with 64 kbps speed that are the basic element in TDM as an analog phone call can be carried over a 64 kbps channek using  PCM. 32 x 64 kbps = 2048 kbps here the limit.  You are correct that a V.35 X.21 synchronous serial interface can have a speed up to 8 Mbps

3)  This is platform and HW dependent. On some HW you configure all the physical properties under the controller e1 object and the IP address under a derived serial object. On other platforms you configure all the physical and logical properties under the serial inteface object.

4) No they have different OSI layer 2

5)  for inter site links the speed is not only related to the distance between the sites but it depends on traffic patterns and application needs. The distance is important from an economical point of view. At 300 km of distance you cannot perform synchronous transfer of databases so there is no need of very high speed as only an incremental asynchrnous approach s possible. So 2 Mbps may be enough or not

Hope to help

Giuseppe

[Kuldeep singh]

Dear Giuseppe,

For Question No3.   is there any concept of Serial E1 and channalized E1  which makes configuration different ???

For Question No4.   plz check these two URL's where discussion about

                              one end is Fastethernet and other end is Serial are Possible, 

                              https://supportforums.cisco.com/message/791745#791745

                              https://supportforums.cisco.com/message/3210698#3210698

                              Still i am not sure that above URL are true or false ?

[Giuseppe Larosa · Accepted solution]

Hello Kuldeep,

4)  my answer was for direct connection between the two ( I didn't catch the distance I'm sorry),  If there is a service provider with an MPLS L3 VPN service for example you can have one end terminated on a serial line and the other site terminated on a fastethernet but it is not what I was meaning from your question  they would be interconnected via SP cloud but not directly connected.  Terminology makes the difference here.

3) You can connect a standard sync Serial interface to an E1 line using a DCE3 modem.

Sync serial hasn't the controller object to be configured as you noted.

The differences are not only limited to this as I have shortly described the differences in configuration are also hardware dependent as far as I can understand with older devices using the controller + derived serial interface objects.

Hope to help

Giuseppe