I have completed a check with the following website: www.bbc.co.uk.....
I also completed a wireshark trace while connecting to the website. So, the actual writing data appears immediately but any Pictures etc take approximately 25 seconds to appear, even though the site should be cached.
So, from my wireshark trace it seems that Windows sends, default, an MSS of 1460. The website is responding to the SYN with a SYN,ACK of 1410. This would, at first glance, seem to be okay. So, it will negotiate at 1410 which is what I have configured on the interface of the PE Router. This is why the initial writing appears immediately. But then, when I look further down the trace to the point where I believe the images should beappearing I see the following:
ACK - Length = 1300 and sometime even less than that for the saem ack number. This would appear to me, maybe, like fragmentation occuring? Here is a seciton of the trace I mean:
Initial SYN/SYN ACK
46 2.382020 192.168.1.11 212.58.244.70 TCP 66 50783 → 443 [SYN] Seq=0 Win=65535 Len=0 MSS=1460 WS=8 SACK_PERM=1
54 2.420046 212.58.244.70 192.168.1.11 TCP 58 443 → 50783 [SYN, ACK] Seq=0 Ack=1 Win=0 Len=0 MSS=1410
Possible Fragmentation occuring:
624 2.941001 212.58.244.70 192.168.1.11 TLSv1.2 1354 Application Data [TCP segment of a reassembled PDU]
625 2.941042 192.168.1.11 212.58.244.70 TCP 54 50783 → 443 [ACK] Seq=1038 Ack=282907 Win=64235 Len=0
626 2.941375 212.58.244.70 192.168.1.11 TCP 819 443 → 50783 [ACK] Seq=282907 Ack=1038 Win=30952 Len=765 [TCP segment of a reassembled PDU]
627 2.941406 192.168.1.11 212.58.244.70 TCP 54 50783 → 443 [ACK] Seq=1038 Ack=283672 Win=65535 Len=0
628 2.943089 212.58.244.70 192.168.1.11 TCP 1354 443 → 50783 [ACK] Seq=283672 Ack=1038 Win=30952 Len=1300 [TCP segment of a reassembled PDU]
629 2.943136 192.168.1.11 212.58.244.70 TCP 54 50783 → 443 [ACK] Seq=1038 Ack=284972 Win=64235 Len=0
630 2.943494 212.58.244.70 192.168.1.11 TCP 1354 443 → 50783 [ACK] Seq=284972 Ack=1038 Win=30952 Len=1300 [TCP segment of a reassembled PDU]
Is this correct operation or should the length still = 1410?