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Network Buffer Size

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  • TCP/IP
  • Servers
  • Networking
Last response: in Networking
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October 10, 2010 1:28:19 AM

The ICSI Netalyzr
Introduction » Analysis » Results
Result Summary +/– (help)

Recorded at 21:19 EDT (01:19 UTC next day), Oct 09 2010. Permalink. Client/server transcript.
Summary of Noteworthy Events –
Minor Aberrations
Certain TCP protocols are blocked in outbound traffic
Network packet buffering may be excessive
Your computer's clock is slightly fast
Address-based Tests +
NAT detection (?): NAT Detected
DNS-based host information (?): OK
Reachability Tests –
TCP connectivity (?): Note
Direct TCP connections to remote FTP servers (port 21) failed.

This is commonly due to how a NAT or firewall handles FTP traffic, as FTP causes unique problems when developing NATs and firewalls.

Direct TCP access to remote SSH servers (port 22) is allowed.
Direct TCP access to remote SMTP servers (port 25) is allowed.
Direct TCP access to remote DNS servers (port 53) is allowed.
Direct TCP access to remote HTTP servers (port 80) is allowed.
Direct TCP access to remote POP3 servers (port 110) is allowed.
Direct TCP access to remote RPC servers (port 135) is allowed.
Direct TCP access to remote NetBIOS servers (port 139) is allowed.
Direct TCP access to remote IMAP servers (port 143) is allowed.
Direct TCP access to remote SNMP servers (port 161) is allowed.
Direct TCP access to remote HTTPS servers (port 443) is allowed.
Direct TCP access to remote SMB servers (port 445) is allowed.
Direct TCP access to remote SMTP/SSL servers (port 465) is allowed.
Direct TCP access to remote secure IMAP servers (port 585) is allowed.
Direct TCP access to remote authenticated SMTP servers (port 587) is allowed.
Direct TCP access to remote IMAP/SSL servers (port 993) is allowed.
Direct TCP access to remote POP/SSL servers (port 995) is allowed.
Direct TCP access to remote OpenVPN servers (port 1194) is allowed.
Direct TCP access to remote PPTP Control servers (port 1723) is allowed.
Direct TCP access to remote SIP servers (port 5060) is allowed.
Direct TCP access to remote BitTorrent servers (port 6881) is allowed.
Direct TCP access to remote TOR servers (port 9001) is allowed.
UDP connectivity (?): OK
Basic UDP access is available.

The applet was able to send fragmented UDP traffic.

The applet was able to receive fragmented UDP traffic.

Direct UDP access to remote DNS servers (port 53) is allowed.
Direct UDP access to remote OpenVPN servers (port 1194) is allowed.
Direct UDP access to remote MSSQL servers (port 1434) is allowed.
Path MTU (?): OK
The path between your network and our system supports an MTU of at least 1500 bytes, and the path between our system and your network has an MTU of 1500 bytes.

Network Access Link Properties –
Network latency measurements (?): Latency: 29ms Loss: 0.0%
The round-trip time (RTT) between your computer and our server is 29 msec, which is good.
We recorded no packet loss between your system and our server.
TCP connection setup latency (?): 37ms
The time it takes your computer to set up a TCP connection with our server is 37 msec, which is good.
Network background health measurement (?): no transient outages
During most of Netalyzr's execution, the applet continuously measures the state of the network in the background, looking for short outages. During testing, the applet observed no such outages.
Network bandwidth measurements (?): Upload 490 Kbit/sec, Download 6.9 Mbit/sec
Your Uplink: We measured your uplink's sending bandwidth at 490 Kbit/sec. This level of bandwidth works well for many users.
Your Downlink: We measured your downlink's receiving bandwidth at 6.9 Mbit/sec. This level of bandwidth works well for many users.
Network buffer measurements (?): Uplink 3200 ms, Downlink 290 ms
We estimate your uplink as having 3200 msec of buffering. This is quite high, and you may experience substantial disruption to your network performance when performing interactive tasks such as web-surfing while simultaneously conducting large uploads. With such a buffer, real-time applications such as games or audio chat can work quite poorly when conducting large uploads at the same time.
We estimate your downlink as having 290 msec of buffering. This level may serve well for maximizing speed while minimizing the impact of large transfers on other traffic.
HTTP Tests +
Address-based HTTP proxy detection (?): OK
Header-based HTTP proxy detection (?): OK
HTTP proxy detection via malformed requests (?): OK
Filetype-based filtering (?): OK
HTTP caching behavior (?): OK
JavaScript-based tests (?): OK
DNS Tests +
Restricted domain DNS lookup (?): OK
Unrestricted domain DNS lookup (?): OK
Direct EDNS support (?): OK
DNS resolver address (?): OK
DNS resolver properties (?): Lookup latency: 110ms
DNS glue policy (?): OK
DNS resolver port randomization (?): OK
DNS lookups of popular domains (?): OK
DNS external proxy (?): OK
DNS results wildcarding (?): OK
Host Properties –
System clock accuracy (?): Warning
Your computer's clock is 18 seconds fast.
Browser properties (?): OK
The following parameters are sent by your web browser to all web sites you visit:
User Agent: Mozilla/5.0 (Windows; U; Windows NT 5.1; en-US) AppleWebKit/534.3 (KHTML, like Gecko) Chrome/6.0.472.63 Safari/534.3
Accept: application/xml,application/xhtml+xml,text/html; q=0.9,text/plain; q=0.8,image/png,*/*; q=0.5
Accept Language: en-US,en;q=0.8
Accept Encoding: gzip,deflate,sdch
Accept Charset: ISO-8859-1,utf-8;q=0.7,*;q=0.3
Java identifies your operating system as Windows XP.
Uploaded Data (?): OK




Network buffering size is excessive
Is their a setting were i can change this? or is that isp controlled





More about : network buffer size

Anonymous
October 10, 2010 6:49:52 AM

Just a thought, but MTU settings -- download TCPOptimizer to guide you.
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October 10, 2010 5:27:41 PM

I have tried that
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Related resources
October 10, 2010 6:05:38 PM

Anyone?
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April 5, 2012 7:35:42 PM

This podcast talks about this issue.

http://www.grc.com/securitynow.htm

Episode #345 Buffer Bloat

Basically, your router manufacturer is forced to used larger memory chips for their buffers.
Small is better in this instance.
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