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Mr. \ Chief of Operating and Maintenance After greetings, I’d like to preset this report to you.

Report on Internet service interruption about Maadi cabinets Problem description: The virtual tunnel between TE Bras router and TE-DATA Bras router was unstable then became down completely. At Thursday 28-3-2013 Problem details: Firstly, Tedata’s engineer (Eng. Saeed) asked us to modify the window size of the tunnel. He claimed that the tunnel size was 256 before our Bras upgrade but now become 1024. And the size mismatch between two routers causes Tunnel instability and the recommended size is 256. So we asked the vendor (Huawei) about the possibility to do that action, Then they answered us that the window size can’t be changed from Huawei Bras since there‘s no option to do that. And the temporary solution to solve the instability problem was resetting the tunnel form our side and Tedata team change the Tunnel window size to 1024 to be the same as ours. The result due to this action was the tunnel become stable for a period less than one hour and then the tunnel dropped completely between two sides and the data service was interrupted. Secondly, Tedata engineer took an action (as he said). He removed the configuration of that tunnel and reconfigures it again but the tunnel didn’t repaired too. We asked Tedata The tunnel’s name and password to insure the matching between two sides, and they replied us with this information to re-enter the password from our side. But nothing happened. So we called the vendor (Huawei) - engineer Ahmed Mahfouz to support us in this problem, then he came and took the logs and reviewed our configuration, He didn’t find something wrong in our configuration but he liked to insure completely so he sent it to the Huawei R&D in china and opened remotely link to them to enable them to review and debug all configuration about our Bras by themselves. Also they didn’t find anything wrong. But they thought that there was mismatch between two sides may be in the tunnel name or password. But we waited Tedata and their vendor (Cisco) to finish their analysis and revision.

After many hours Tedata confirmed that their configurations were reviewed and there was no wrong also. Then they reboot their Bras completely (As they said also) and no good news. Thirdly, we suggested some solutions to solve the problem and decided to excite them one by one and try. And we are lucky since the first suggestion solved the problem.

Solution: This suggestion was changing the password of the tunnel from the two sides to overcome the mismatch problem between two Bras routers. After that we noticed that the tunnel recovered and the basic problem was solved. So we became sure that the password which Tedata gave us was wrong. Then Tedata engineer told us that the password which he gave us was encrypted password not the original!!!!!!!!! Then he searched about the old original (unencrypted) password and gave us it again to re-enter it, then we modified it. But the partial problem still exist which Tedata Bras see our window size is 1024 not 256 so they changed their size to match our size. But the recommended size is 256 as Tedata said. This issue is presented to Huawei team to find the solutions in their product (Bras).

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