Re: [WISPA] Double Ping Replies

2006-06-08 Thread Scott Reed




Thanks again, Jack.

I am going to be working on the fade margin and will post results when I have them.  Hopefully by next weekend.

Scott Reed 


Owner 


NewWays 


Wireless Networking 


Network Design, Installation and Administration 


www.nwwnet.net 




-- Original Message 
---

From: Jack Unger [EMAIL PROTECTED] 


To: WISPA General List wireless@wispa.org 


Sent: Thu, 08 Jun 2006 14:48:44 -0700 


Subject: Re: [WISPA] Double Ping Replies 



 Scott, 
 
 

Thanks for letting me know that this problem is occuring along a chain  
 

of three wireless hops and not just two hops. Unfortunately, this makes  

 

trying to diagnose and correct the problem remotely (via email) even  
 

more complex. Without me being on site in real time to test and  

 

analyze the data with you, I can only give you general suggestions for  
 

you to follow through on. 
 
 

1. The 7.7 dBi downstream fade margin from the DLB1300 to the CM9/RB230  

 

is too low for this 11.3 mile long link. Radio Mobile shows a link  

 

distance of 18.22 km which is 11.3 miles. My fade margin rule of 
thumb  
 

says this link needs a fade margin of at least 11 dB for reliable  
 

operation. I suggest that you work on correcting this first, as I  
 

outlined in my first email. 
 
 

2. When testing link quality (as opposed to just testing connectivity)  
 

always use large (1400 byte) ping packets. Large packets will give you a  

 

  more accurate indication of how the network will perform when handling  

 

real-world customer traffic. 
 
 

3. In the future, on newly-built networks, test throughput in both  
 

directions and make network adjustments before adding customers onto the  

 

network. It's a lot easier to fix network problems before customers are  

 

complaining rather than after they've been complaining. 
 
 

Feel free to update me after you increase the long link fade margin. 

 
 

Good luck, 
 

            jack 
 
 

Scott Reed wrote: 
 
 

 Thanks Jack. See inline for responses. Also, 2 others asked questions so: 

 

 1) I have not found anything to indicate this is getting treated as a  

 

 broadcast or network IP. 
 

 2) Other customers connected to the AP. And yes, they get double ping  

 

 replies across the long link. 
 

  
 

 Scott Reed 
 

 Owner 
 

 NewWays 
 

 Wireless Networking 
 

 Network Design, Installation and Administration 
 

 www.nwwnet.net http://www.nwwnet.net/ 

 

  
 

  
 

 -- Original Message --- 
 

 From: Jack Unger [EMAIL PROTECTED] 
 

 To: WISPA General List wireless@wispa.org 
 

 Sent: Mon, 05 Jun 2006 19:43:02 -0700 
 

 Subject: Re: [WISPA] Double Ping Replies 
 

  
 

   Scott, 
 

   
 

   RADIOMOBILE PLOT - The Radio Mobile plot FROM your midpoint CPE 
back to 
 

   your DLB1300 AP was very helpful and shows a fade margin of 10.7 
dB 
 

   which should be enough to provide reliable performance in the 
upstream 
 

   direction, assuming that the noise level is low (below the 
receiver 
 

   threshold) at the near-end DLB1300. 
 

  
 

   
 

   DOWNSTREAM FADE MARGIN - What's the fade margin in the 
downstream 
 

   direction from the DLB1300 TO the midpoint CPE? 
 

 Fade margin in reverse direction is 7.7dB. 
 

 The fade margin will 
 

   only be the same as the upstream fade margin if the DLB1300 
transmitter 
 

   power output is as high or higher than the CPE transmitter power 
output 
 

   AND if the midpoint CM9 receiver sensitivity (threshold) is as 
good as 
 

   the DLB1300 receiver threshold. Can you do a Radio Mobile plot 
in the 
 

   downstream direction to verify that the downstream fade margin 
is at 
 

   least 10 dB? 
 

   
 

   ADDITIONAL TESTING - Do you still get double pings if you ping 
from the 
 

   first (near end) AP to the midpoint CM9 radio? Yes. 
 

 Do you get double pings 
 

   if you ping from the near-end DLB1300 AP to the second 
(midpoint) AP? 
 

 Yes 
 

   
 

   PROBLEM HISTORY - What's the history of the problem? Was the 
system 
 

   working well for a certain period of time and THEN did it start 
slowing 
 

   down or is this a newly-installed link that has not yet been 
proven to 
 

   deliver full throughput and reliable performance in both 
directions? 
 

 I am not sure. We put up the customers and all was fine, so I don't know  

 

 that I have done any pings in the 6 months that they have been up. This  

 

 week one customer called to say his connection was slow. He had  
 

 mentioned that before and I had not noticed the ping problem, but I  

 

 assume they are related. I have a new customer, less than 2 weeks that  

 

 has determined he is getting packet loss, probably on the long link.  

 

 Just heard that, so have not done any other investigation on his, though  

 

 it does double reply sometimes. 
 

   If the system worked well for a while and then deteriorated, I'd 
look  
 

 for: 
 

   
 

   a) A hardware problem

Re: [WISPA] Double Ping Replies

2006-06-06 Thread Marlon K. Schafer (509) 982-2181



Are there any other customers on the second 
hop?

Does the same thing happen to them?

Marlon(509) 
982-2181 
Equipment sales(408) 907-6910 
(Vonage) 
Consulting services42846865 
(icq) 
And I run my own wisp!64.146.146.12 (net meeting)www.odessaoffice.com/wirelesswww.odessaoffice.com/marlon/cam



  - Original Message - 
  From: 
  Scott Reed 
  To: WISPA General List 
  Sent: Monday, June 05, 2006 5:06 PM
  Subject: Re: [WISPA] Double Ping 
  Replies
  This is an 802.11b hop link. It goes 9.4 miles 
  from a DLB1300 AP with 120* 14dBi sector to a 24dBi Grid on an CM9 in a RB230. 
  From there it is 2.0 miles to the customer. The AP has a 90* 9dBi (I think) on 
  a CM9. Customer is a 15dBi grid to an SB Outdoor radio. Does the 9.4 
  mile link constitute a "long link?" It appears the double ping replies are 
  only if I ping from the first AP through the other to the client. Pinging from 
  the clients near AP doesn't get the double replies. RadioMobile plot 
  of link attached. Scott Reed Owner NewWays Wireless 
  Networking Network Design, Installation and Administration www.nwwnet.net 
  -- Original Message --- From: Jack 
  Unger [EMAIL PROTECTED] To: WISPA General List 
  wireless@wispa.org Sent: Mon, 05 Jun 2006 15:31:06 -0700 
  Subject: Re: [WISPA] Double Ping Replies  Scott,  
   Excessive pings is often a symptom of a poor wireless link. I would 
   check to be sure that:   a) The customer's antenna is 
  high enough to provide a good signal back  to the access point 
b) The link is not overly long   c) There is 
  no hardware problem in their antenna system or radio.   jack 
Scott Reed wrote:   I had a customer call to say 
  there connection had not been working well   today. I started to 
  see what is going on by ping the radio. I get 2   replies for 
  almost every ping. Average was about 1 at 45ms and one at   56ms. 
  The times are longer than normal, but my question is, how do I   
  get 2 reponses to a ping? No duplicate addresses, I checked.   The 
  other way I know there were 2 pings is one of the MTs that is   
  between me and the customer showed 2 times the download as upload speed 
in torch, and I was the only one talking to that radio.  
   Suggestions on what I need to look for? Scott 
  Reed   Owner   NewWays   Wireless 
  Networking   Network Design, Installation and Administration 
www.nwwnet.net http://www.nwwnet.net/ 
  --  Jack Unger ([EMAIL PROTECTED]) - President, Ask-Wi.Com, Inc. 
   Serving the License-Free Wireless Industry Since 1993  Author 
  of the WISP Handbook - "Deploying License-Free Wireless WANs"  True 
  Vendor-Neutral WISP Consulting-Training-Troubleshooting  Our next WISP 
  Workshop is June 21-22 in Atlanta, GA.  Phone (VoIP Over Broadband 
  Wireless) 818-227-4220 www.ask-wi.com   --  WISPA Wireless 
  List: wireless@wispa.org   Subscribe/Unsubscribe:  http://lists.wispa.org/mailman/listinfo/wireless  
   Archives: http://lists.wispa.org/pipermail/wireless/ --- 
  End of Original Message --- 
  
  

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Re: [WISPA] Double Ping Replies

2006-06-06 Thread Jeromie Reeves
Is this ip somehow setup as a network or broadcast IP? Ive seen that 
cause 2 ping replys


Jeromie

Scott Reed wrote:

I had a customer call to say there connection had not been working 
well today.  I started to see what is going on by ping the radio.  I 
get 2 replies for almost every ping.  Average was about 1 at 45ms and 
one at 56ms.  The times are longer than normal, but my question is, 
how do I get 2 reponses to a ping?  No duplicate addresses, I checked.
The other way I know there were 2 pings is one of the MTs that is 
between me and the customer showed 2 times the download as upload 
speed in torch, and I was the only one talking to that radio.

Suggestions on what I need to look for?

Scott Reed
Owner
NewWays
Wireless Networking
Network Design, Installation and Administration
www.nwwnet.net http://www.nwwnet.net/



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Re: [WISPA] Double Ping Replies

2006-06-05 Thread Jack Unger

Scott,

Excessive pings is often a symptom of a poor wireless link. I would 
check to be sure that:


a) The customer's antenna is high enough to provide a good signal back 
to the access point


b) The link is not overly long

c) There is no hardware problem in their antenna system or radio.


jack


Scott Reed wrote:
I had a customer call to say there connection had not been working well 
today.  I started to see what is going on by ping the radio.  I get 2 
replies for almost every ping.  Average was about 1 at 45ms and one at 
56ms.  The times are longer than normal, but my question is, how do I 
get 2 reponses to a ping?  No duplicate addresses, I checked.
The other way I know there were 2 pings is one of the MTs that is 
between me and the customer showed 2 times the download as upload speed 
in torch, and I was the only one talking to that radio.

Suggestions on what I need to look for?

Scott Reed
Owner
NewWays
Wireless Networking
Network Design, Installation and Administration
www.nwwnet.net http://www.nwwnet.net/



--
Jack Unger ([EMAIL PROTECTED]) - President, Ask-Wi.Com, Inc.
Serving the License-Free Wireless Industry Since 1993
Author of the WISP Handbook - Deploying License-Free Wireless WANs
True Vendor-Neutral WISP Consulting-Training-Troubleshooting
Our next WISP Workshop is June 21-22 in Atlanta, GA.
Phone (VoIP Over Broadband Wireless) 818-227-4220  www.ask-wi.com




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Re: [WISPA] Double Ping Replies

2006-06-05 Thread Marlon K. Schafer (509) 982-2181



I've seen that with the really old 2 meg 
Teletronics ap's. It was a timing issue on a really long link. And 
was unique to a firm ware version or two.

What would happen was that the radio would send out 
the ping, not get a reply soon enough and send out a second one. Then it 
would get both back.

I've also heard of multipath causing something like 
that, only one goes out but two come back.

Both of these scenarios can (and did) cause really 
strange performance issues.

laters,
Marlon(509) 
982-2181 
Equipment sales(408) 907-6910 
(Vonage) 
Consulting services42846865 
(icq) 
And I run my own wisp!64.146.146.12 (net meeting)www.odessaoffice.com/wirelesswww.odessaoffice.com/marlon/cam



  - Original Message - 
  From: 
  Scott Reed 
  To: wireless@wispa.org 
  Sent: Monday, June 05, 2006 2:43 PM
  Subject: [WISPA] Double Ping 
Replies
  I had a customer call to say there connection had 
  not been working well today. I started to see what is going on by ping 
  the radio. I get 2 replies for almost every ping. Average was 
  about 1 at 45ms and one at 56ms. The times are longer than normal, but 
  my question is, how do I get 2 reponses to a ping? No duplicate 
  addresses, I checked. The other way I know there were 2 pings is one of 
  the MTs that is between me and the customer showed 2 times the download as 
  upload speed in torch, and I was the only one talking to that radio. 
  Suggestions on what I need to look for? Scott Reed Owner 
  NewWays Wireless Networking Network Design, Installation and 
  Administration www.nwwnet.net 
  
  

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Re: [WISPA] Double Ping Replies

2006-06-05 Thread Jack Unger

Scott,

RADIOMOBILE PLOT - The Radio Mobile plot FROM your midpoint CPE back to 
your DLB1300 AP was very helpful and shows a fade margin of 10.7 dB 
which should be enough to provide reliable performance in the upstream 
direction, assuming that the noise level is low (below the receiver 
threshold) at the near-end DLB1300.


DOWNSTREAM FADE MARGIN - What's the fade margin in the downstream 
direction from the DLB1300 TO the midpoint CPE? The fade margin will 
only be the same as the upstream fade margin if the DLB1300 transmitter 
power output is as high or higher than the CPE transmitter power output 
AND if the midpoint CM9 receiver sensitivity (threshold) is as good as 
the DLB1300 receiver threshold. Can you do a Radio Mobile plot in the 
downstream direction to verify that the downstream fade margin is at 
least 10 dB?


ADDITIONAL TESTING - Do you still get double pings if you ping from the 
first (near end) AP to the midpoint CM9 radio? Do you get double pings 
if you ping from the near-end DLB1300 AP to the second (midpoint) AP?


PROBLEM HISTORY - What's the history of the problem? Was the system 
working well for a certain period of time and THEN did it start slowing 
down or is this a newly-installed link that has not yet been proven to 
deliver full throughput and reliable performance in both directions?

If the system worked well for a while and then deteriorated, I'd look for:

a) A hardware problem, or

b) An antenna alignment problem, or

c) A high-noise level problem (the noise increased recently), or

d) Water intrusion, or

e) Some combination of a, b, c, or d.

On the other hand, if the system is newly-installed and is not working 
(and has never worked) the way you expected it to, the problem can still 
be caused by a, b, c, d, or e (above) but it can also be something at 
the wired Ethernet level or at the software configuration level.



FINAL QUESTIONS

1. Are you absolutely sure that the customer's antenna is high enough to 
have a wireless LOS path (including an unobstructed Fresnel Zone) back 
to the mid-point AP? Is it possible that the 2-mile link is shooting 
through too many treetops?


2. What is the normal ping time range?

3. How large are your ping packets?

4. What hardware is located between the midpoint CPE and the midpoint 
AP?



NEXT STEP - I think that the ping test results that you obtain when you 
ping from the near-end AP to the midpoint CPE and then from the near-end 
AP to the midpoint AP should be helpful in further isolating the problem.


jack






Scott Reed wrote:

This is an 802.11b hop link. It goes 9.4 miles from a DLB1300 AP with 
120* 14dBi sector to a 24dBi Grid on an CM9 in a RB230. From there it is 
2.0 miles to the customer. The AP has a 90* 9dBi (I think) on a CM9. 
Customer is a 15dBi grid to an SB Outdoor radio.


Does the 9.4 mile link constitute a long link? It appears the double 
ping replies are only if I ping from the first AP through the other to 
the client. Pinging from the clients near AP doesn't get the double 
replies.


RadioMobile plot of link attached.

Scott Reed
Owner
NewWays
Wireless Networking
Network Design, Installation and Administration
www.nwwnet.net http://www.nwwnet.net/


-- Original Message ---
From: Jack Unger [EMAIL PROTECTED]
To: WISPA General List wireless@wispa.org
Sent: Mon, 05 Jun 2006 15:31:06 -0700
Subject: Re: [WISPA] Double Ping Replies

  Scott,
 
  Excessive pings is often a symptom of a poor wireless link. I would
  check to be sure that:
 
  a) The customer's antenna is high enough to provide a good signal back
  to the access point
 
  b) The link is not overly long
 
  c) There is no hardware problem in their antenna system or radio.
 
  jack
 
  Scott Reed wrote:
   I had a customer call to say there connection had not been working 
well

   today. I started to see what is going on by ping the radio. I get 2
   replies for almost every ping. Average was about 1 at 45ms and one at
   56ms. The times are longer than normal, but my question is, how do I
   get 2 reponses to a ping? No duplicate addresses, I checked.
   The other way I know there were 2 pings is one of the MTs that is
   between me and the customer showed 2 times the download as upload 
speed

   in torch, and I was the only one talking to that radio.
   Suggestions on what I need to look for?
  
   Scott Reed
   Owner
   NewWays
   Wireless Networking
   Network Design, Installation and Administration
   www.nwwnet.net http://www.nwwnet.net/ http://www.nwwnet.net/
  
 
  --
  Jack Unger ([EMAIL PROTECTED]) - President, Ask-Wi.Com, Inc.
  Serving the License-Free Wireless Industry Since 1993
  Author of the WISP Handbook - Deploying License-Free Wireless WANs
  True Vendor-Neutral WISP Consulting-Training-Troubleshooting
  Our next WISP Workshop is June 21-22 in Atlanta, GA.
  Phone (VoIP Over Broadband Wireless) 818-227-4220 www.ask-wi.com 
http://www.ask-wi.com/

 
  --
  WISPA Wireless List: wireless@wispa.org