Hi,
We have a software where Client is used to copy a file to and from
a server. The communication happens over SSL layer. I am analyzing an
issue where file copying is "very" slow using our client-server software
when compared with some other tools.
What I have observed is that, the packets captured follow a pattern.
First there will be a packet with a payload data of 16384 bytes
(reassembled from 12 assembled TCP segments) and the next one will
be a packet with payload data of 71 bytes only. And this pattern repeats
itself. I am worried about the packet with 71 bytes, is it causing some
delay?
For example,
Following is excerpt from first type (reassembled, 16384 bytes) of
packet's wireshark output:
XXXXXXXXXXXXXXXXXXXXXXXXXXXXXXXXXXXXXXXXXXXX
[12 Reassembled TCP Segments (16421 bytes): #76576(1460), #76577(1460), #76578(1460), #76579(1460), #76580(1460), #76581(1460), #76582(1460), #76583(1460), #76584(1460), #76585(1460), #76586(1460), #76587(361)]
[Frame: 76576, payload: 0-1459 (1460 bytes)]
[Frame: 76577, payload: 1460-2919 (1460 bytes)]
[Frame: 76578, payload: 2920-4379 (1460 bytes)]
[Frame: 76579, payload: 4380-5839 (1460 bytes)]
[Frame: 76580, payload: 5840-7299 (1460 bytes)]
[Frame: 76581, payload: 7300-8759 (1460 bytes)]
[Frame: 76582, payload: 8760-10219 (1460 bytes)]
[Frame: 76583, payload: 10220-11679 (1460 bytes)]
[Frame: 76584, payload: 11680-13139 (1460 bytes)]
[Frame: 76585, payload: 13140-14599 (1460 bytes)]
[Frame: 76586, payload: 14600-16059 (1460 bytes)]
[Frame: 76587, payload: 16060-16420 (361 bytes)]
[Segment count: 12]
[Reassembled TCP length: 16421]
[Reassembled TCP Data: 1703014020248070ffbaa440b4f2edc9aed51827627e3ef2...]
Secure Sockets Layer
TLSv1 Record Layer: Application Data Protocol: data
Content Type: Application Data (23)
Version: TLS 1.0 (0x0301)
Length: 16416
Encrypted Application Data: 248070ffbaa440b4f2edc9aed51827627e3ef2831e473708...
Data (16384 bytes)
XXXXXXXXXXXXXXXXXXXXXXXXXXXXXXXXXXXXXXXXXXXX
And following is from the very next packet (71 bytes):
XXXXXXXXXXXXXXXXXXXXXXXXXXXXXXXXXXXXXXXXXXXX
Secure Sockets Layer
TLSv1 Record Layer: Application Data Protocol: data
Content Type: Application Data (23)
Version: TLS 1.0 (0x0301)
Length: 96
Encrypted Application Data: 0f92c19d11ffd0cc38e854549738eb7a0b5ca1979020ef24...
Data (71 bytes)
XXXXXXXXXXXXXXXXXXXXXXXXXXXXXXXXXXXXXXXXXXXX
This pattern of 16384 byte SSL record(?) followed by a 71 byte SSL
record(?)
keeps on repeating itself till the whole file is uploaded.
Could this be
slowing down the file transfer? Moreover, why could
this thing be
happening? Any pointers?
Sorry if this is something very simple that I can't understand, I am
very
new to this thing. Thanks for taking time to go through this
rather lengthymessage.
-Prabhat
