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BT ADSL prob: ATM OAM F5 segment ping - OAM F4 FAIL

First my router details:

TP-LINK TD-W8920G (A) ver 2.2 UK

Hardware version reported at as
TD-W8920G v1 0000235b

Sticker on bottom of unit
TP-LINK TD-W8920G (A) ver 2.2

BT ADSL Broadband in UK

Current router firmware version reported at
1.3.3 Build 080227 Rel.40823n
(as supplied new in box early Nov 08)

Manufacturer support:

Now my ISP details:

British Telecom ('BT') option 3 ADSL

Now the problem:

First a bit of history. For 2 or 3 months, experiencing slow, 'sticking' pageloads in all browsers. Unable to connect to remote webserver via FTP reliably despite changing computers, FTP client software. FTP port mode just about worked, Passive mode would not even connect most of the time. I was experiencing these problems for ages using a belkin router, and blamed that - so I bought the router listed above. No improvement.

Eventually noted that the router's WAN diagnostics interface was showing 'FAIL' for 'ping primary DNS server'. Tried to manually ping both the primary and secondary DNS servers via XP cmd interface, both failed - no reply.

Decided to untick the WAN configuration checkbox in the router for 'automatically assigned DNS servers', and replaced the DNS server addresses supplied by BT with addresses supplied by the 'OpenDNS' public DNS service.

Great improvement - FTP now working smoothly on both passive and port mode. Webpages loading much faster and no 'stalls'.

However, still sticks occasionally.

Looking in the TP-Link router's diagnostics interface, I see the two following failures:

ATM OAM F5 segment ping - OAM F4 FAIL
ATM OAM F5 end-to-end ping - OAM F4 FAIL

If I run the diagnostics without specifying 'OAM F4', both of those tests appear to pass.

What gives? Do I have a fault somewhere that I can complain about and get fixed? Do I possibly have a setting wrong in my WAN connection details? I use the following connection details:

VPI/VCI 0/38
UBR without PCR
MTU 1492
IGMP enabled
QoS disabled
Encapsulation VC/MUX
PPP user:
PPP password: BT (as per everyone else)

Thanks for any ideas.

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Are you using the router through a BT line? if you are BT will be able to sort this problem for you by sending the router an update that it sounds like it needs

hope this helps

Posted on Nov 20, 2008


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