low mtu of 1246 on bsnl broadband and other problems

22ji

Newbie
[OP]
Regulars
Jun 12, 2006
86
0
hi,
i am using bsnl since 2005 (my only option) and recently i changed my plan from home ul 750 (512 kbps) to 1350 ul (4mpbs upto 20gb, 512 afterwards)
now my ip address is changed from 59.xx.xx.xx to 117.xx.xx.xx.
i was unable to browse any website except google and then i downloaded tcpoptimizer and it told me to set my MTU to 1246 (ideally 1492)
after doing this i can browse/download @ full speed but i cant change mtu on my ios device so i cant use internet on it.
also i get very high ping with airtel users across india when i play online games (not the case when i was on home 750 ul plan), but with bsnl,mtnl,others i get ping around 100ms which i consider good.
i know my noise margin/line attenuation is not optimal but i do not encounter frequent disconnection,etc
i am also unable to check my usage,etc as on old and new portal its says username disabled/does not exist.
if i change my plan back to what it was ie home 750 ul will all my problems go away!!!!
i will appreciate any help.
thanks

router stats

Modem StatusConnected
DownStream Connection Speed8128 kbps
UpStream Connection Speed992 kbps
VPI0
VCI35



Network Type PPPoE
IP Subnet Mask 255.255.255.255
Gateway IP Address117.197.112.1
Domain Name Server 218.248.255.197
218.248.255.196



ADSL LinkDownstreamUpstream
Connection Speed8128 kbps992 kbps
Line Attenuation40 db13.5 db
Noise Margin8 db7 db



http://www.speedtest.net
 

essbebe

MODERATOR
Regulars
Aug 20, 2006
9,804
81
to set my MTU to 1246 (ideally 1492)Presume typing mistake. could be 1426.Your modem Attn is high. contact BSNL CC to check the line.
 


meetdilip

Computer Addict
Regulars
Apr 15, 2009
4,309
159
1. Go to speedtest.net, perform a speed test and post the forum code here.

2. To check your usage, you should first determine your portal. Please mention your SSA, I can help you find your portal.

3. You have been changed from NIB - I to NIB - II. It is much superior to former. It is quite unfortunate that it is causing problems. Ask someone at exchange to change your port and check.

4. Changing back to UL 750 won't help.

5. Try talking to the SDE about your problem. Normally they help.

6. If still no go, complaint here (known for better response)

http://mis.bsnl.co.in/pgs/internet/pgwebregn.asp
 

essbebe

MODERATOR
Regulars
Aug 20, 2006
9,804
81
no its 1246 and bsnl checked and told me that line is fine
Please mention your modem/model/make/number.
Usually recommended RANGE MTU 1400 to 1500.
Default for Windows XP etc 1492.
2.
Please test as given below and give feedback.
No changes made in your set up.
Microsoft Windows [Version 6.1.7601]
Copyright (c) 2009 Microsoft Corporation. All rights reserved.

C:\Users\Kavika>ping broadbandforum.in -f -l 1492

Pinging broadbandforum.in [173.245.60.112] with 1492 bytes of data:
Packet needs to be fragmented but DF set.
Packet needs to be fragmented but DF set.
Packet needs to be fragmented but DF set.
Packet needs to be fragmented but DF set.

Ping statistics for 173.245.60.112:
Packets: Sent = 4, Received = 0, Lost = 4 (100% loss),

C:\Users\Kavika>ping broadbandforum.in -f -l 1246

Pinging broadbandforum.in [173.245.60.112] with 1246 bytes of data:
Reply from 173.245.60.112: bytes=1246 time=294ms TTL=49
Reply from 173.245.60.112: bytes=1246 time=294ms TTL=49
Reply from 173.245.60.112: bytes=1246 time=295ms TTL=49
Reply from 173.245.60.112: bytes=1246 time=294ms TTL=49

Ping statistics for 173.245.60.112:
Packets: Sent = 4, Received = 4, Lost = 0 (0% loss),
Approximate round trip times in milli-seconds:
Minimum = 294ms, Maximum = 295ms, Average = 294ms


General instruction for finding your optimal MTU size

Go to Start and select Run.
Set router to MTU 1500 to start with.
Start RUN
Type in cmd (Windows 2000/XP/Vista/7) or
command (Windows 98/ME) into the box .
Hit the enter key or click OK
At the DOS prompt,
type in ping bbc.co.uk -f -l 1492
and hit the Enter key.
If you get the response "Packet needs to be fragmented but DF set",
lower the size the packet in increments of +/-10 (e.g. 1472, 1462, 1440, 1400)
until you have a packet size that does not fragment.

Now increase the packet size from this number in small increments until you
find the largest size that does not fragment.

Add 28 to that number (IP/ICMP headers) to get the optimal MTU setting.
For example, if the largest packet size from ping tests is 1462, add 28 to
1462 to get a total of 1490 which is the optimal MTU setting and can be put
in your router's settings
!
Hope this helps some of you!?

Source : NETGEAR site.

One more: tried MTU 1400
C:\Users\Kavika>ping broadbandforum.in -f -l 1400

Pinging broadbandforum.in [199.27.134.39] with 1400 bytes of data:
Reply from 199.27.134.39: bytes=1400 time=295ms TTL=50
Reply from 199.27.134.39: bytes=1400 time=296ms TTL=50
Reply from 199.27.134.39: bytes=1400 time=295ms TTL=50
Reply from 199.27.134.39: bytes=1400 time=296ms TTL=50

Ping statistics for 199.27.134.39:
Packets: Sent = 4, Received = 4, Lost = 0 (0% loss),
Approximate round trip times in milli-seconds:
Minimum = 295ms, Maximum = 296ms, Average = 295ms
 


22ji

Newbie
[OP]
Regulars
Jun 12, 2006
86
0
@meetdilip

speedtest http://www.speedtest.net

i am based in distt.mohali,punjab (main exchange patiala)

----------

@essbebe

i did this test by using tcpoptimizer and it recommended to set my mtu 1246
if i set it anything other than 1246,websites wont open except google)
my modem/router is netgear dg834g v3 (with latest firmware)
 

essbebe

MODERATOR
Regulars
Aug 20, 2006
9,804
81
Thanks for the feedback.TEST:If you check MTU 1400 same way I tested , this unusual MTU1246 can be noted for future reference in forum.( you are NOT changing your settings in the modem/router and your connectivity will not be lost ) WHAT is the MTU selected by your OS ( in registry) is another subject.
 

22ji

Newbie
[OP]
Regulars
Jun 12, 2006
86
0
here is the copied text from tcpoptimizerPinging [68.67.73.20] with 1500 bytes -> ..fragmentedPinging [68.67.73.20] with 750 bytes ->bytes=750 time=459ms TTL=48Pinging [68.67.73.20] with 1125 bytes ->bytes=1125 time=450ms TTL=48Pinging [68.67.73.20] with 1312 bytes -> ..fragmentedPinging [68.67.73.20] with 1218 bytes ->bytes=1218 time=453ms TTL=48Pinging [68.67.73.20] with 1265 bytes -> ..fragmentedPinging [68.67.73.20] with 1241 bytes -> ..fragmentedPinging [68.67.73.20] with 1229 bytes -> ..fragmentedPinging [68.67.73.20] with 1223 bytes -> ..fragmentedPinging [68.67.73.20] with 1220 bytes -> ..fragmentedPinging [68.67.73.20] with 1219 bytes -> ..fragmentedThe largest possible non-fragmented packet is 1218 (1246 - 28 ICMP & IP headers).You can set your MTU to 1246
 

essbebe

MODERATOR
Regulars
Aug 20, 2006
9,804
81
Downloaded full manual for Dg834g 214 pages 5.1MB
also chapter extract. about MTU.
http://documentation.netgear.com/dg834g/enu/202-10155-01/pdfs/Advanced.pdf 194 KB 16 pages
NetGear as well as google search, does not recommend this value.
Rarely we see value below 1400.

Just wanted you to TEST in command prompt for MTU 1246 and 1400.
START RUN type cmd Ok
New window
type ping broadbandforum.in -f -l 1246
type ping broadbandforum.in -f -l 1400