[Codel] blip: a tool for seeing internet latency with javascript

[Codel] blip: a tool for seeing internet latency with javascript

[Dave Taht]

Apenwarr has developed a really unique tool for seeing latency and
packet loss via javascript. I had no idea this was possible:

http://apenwarr.ca/log/?m=201304#26



-- 
Dave Täht

Fixing bufferbloat with cerowrt: http://www.teklibre.com/cerowrt/subscribe.html

Re: [Codel] [Bloat] blip: a tool for seeing internet latency with javascript

[Rich Brown]

This is indeed a cool hack. I was astonished for a moment, because it was a bedrock belief that you can't send pings from Javascript. And in fact, that is still true.

Apenwarr's code sends short HTTP queries of the format shown below to each of two hosts: 

http://gstatic.com/generate_204
http://apenwarr.ca/blip/

The Blip tool shows ~60-70ms for the gstatic host, and ~130 msec for the latter. Ping times are ~52 msec and 125msec, respectively. These times seem to track response times by my eye (no serious analysis) to load both on my primary (bloated) router and CeroWrt.

Still a cool hack.

Rich

-------------------------
HTTP Request & Response for typical blip "ping"

OPTIONS /generate_204 HTTP/1.1
Host: gstatic.com
Connection: keep-alive
Access-Control-Request-Method: GET
Origin: http://gfblip.appspot.com
User-Agent: Mozilla/5.0 (Macintosh; Intel Mac OS X 10_8_3) AppleWebKit/537.31 (KHTML, like Gecko) Chrome/26.0.1410.65 Safari/537.31
Access-Control-Request-Headers: accept, origin, x-requested-with
Accept: */*
Referer: http://gfblip.appspot.com/
Accept-Encoding: gzip,deflate,sdch
Accept-Language: en-US,en;q=0.8
Accept-Charset: ISO-8859-1,utf-8;q=0.7,*;q=0.3

HTTP/1.1 204 No Content
Content-Length: 0
Content-Type: text/html; charset=UTF-8
Date: Sun, 28 Apr 2013 12:37:17 GMT
Server: GFE/2.0


On Apr 26, 2013, at 7:04 PM, Dave Taht <dave.taht@gmail.com> wrote:

> Apenwarr has developed a really unique tool for seeing latency and
> packet loss via javascript. I had no idea this was possible:
> 
> http://apenwarr.ca/log/?m=201304#26
> 
> 
> 
> -- 
> Dave Täht
> 
> Fixing bufferbloat with cerowrt: http://www.teklibre.com/cerowrt/subscribe.html
> _______________________________________________
> Bloat mailing list
> Bloat@lists.bufferbloat.net
> https://lists.bufferbloat.net/listinfo/bloat

Re: [Codel] [Bloat] blip: a tool for seeing internet latency with javascript

[Fred Baker (fred)]

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On Apr 26, 2013, at 4:04 PM, Dave Taht <dave.taht@gmail.com<mailto:dave.taht@gmail.com>> wrote:

Apenwarr has developed a really unique tool for seeing latency and
packet loss via javascript. I had no idea this was possible:

http://apenwarr.ca/log/?m=201304#26

Indeed, very cool.

For those on PCs running Windows, there is also pingplotter (http://www.pingplotter.com). It sends what amounts to a trace route once a second - a burst of packets back to back with TTLs varying from 1 to the number of hops between you and whatever you're targeting. It tracks not only the end to end behavior but the behavior along the way. If you like, you can leave it running and have it send you an email with a .png of an event that is worse than some threshold. I've attached a graphic it showed me once about a particular path I cared about that happened to have a geosynchronous satcom delay in it.

BTW, the data here is most definitely dated. A ping I just did gave me

--- 212.88.97.49 ping statistics ---
100 packets transmitted, 100 packets received, 0.0% packet loss
round-trip min/avg/max/stddev = 364.163/372.373/398.910/5.712 ms


[cid:717DCED7-6136-433E-A8A4-9FF5795D689A@cisco.com]

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