A: The Internet has defined 5 classes of IP address based on the
first 3 bits of the IP address. The three most commonly used classes are A, B and C.
Class A addresses have 16,777,216 host addresses available (in
tech jargon the host id is 24 bits long).
Class B addresses have 65,536 host addresses available (in tech
jargon the host id is 16 bits long).
Class C addresses have 256 addresses available (in tech jargon the
host id part is 8 bits long).
Increasingly Class D addresses are becoming more common because
they are used in IP Multicasting.
Q8: Can I monitor
the performance and availability of my Web site (or ftp site) using Zing?
A: You can do anything with Zing. Yes, to change the target IP
address used by Zing select the ‘Info’ button, then from the Options menu,
select ‘System Defaults’. Enter the IP address you want to monitor in the
‘Target IP’ address box. Zing will continue to use this address (even on reload)
until give it another address.
Q9: Can I change
the interval between ‘Network Probes’ in Zing.
A: Yes, to change the time between ‘Network Probes’
select the ‘Info’ button, then from the Options menu select ‘System
Defaults’. Enter the required value in seconds (must lie in the range 1 to 300) in
the ‘Network timer’ box. NOTE: Zing checks the minimum interval so as not to
keep any connections open unnecessarily and will not let you set a timer value less that
the minimum ‘Threshold Period’ (default is 30 seconds).
Q10: How do I
change the Threshold Timer interval in Zing?
A: On versions of CoolFig before 1.1.2 select the
SNMP display for the Router and expand the ‘zmpTable’ entry (zytrax/router/zmp).
Double click the entry zmpThresholdPeriod and change the required entry (ies) to the value
you want. From CoolFig version 1.1.2 onward the Router Wizard provides the ability to set
this value under the ‘Advanced Options’ button in Step 6 for any Route. Once the
configuration has been defined in the Router Summary screen expand the ‘Remote
Route’ entry for which you want to make the change until you see the entry Threshold
Period, double click this entry and enter the required value.
Q11: What is a
Network Probe?
A: Zing issues Network Probe sequences to discover the status of
the network through to the nominated Target IP address. a Network Probe sequence consists
of a series of Pings (ICMP Echo requests) with an increasing Time to Live count until the
required end point is reached.
Q12: How do I tell
the IP address and performance of any of the Router hops?
A: Zing provides two methods. The first method involves placing
the mouse over the Router hop in which you are interested, after about 1 second the IP
address, Current Ping response time (C=) Average Response Time (A=) and Average Window
Response Time (WA=) are displayed. The second method involves clicking the
‘Info’ button. statistics for all the Router hops to the Target IP address are
displayed in the Network Stats window.
Q13: In Zing how
to I tell my average Router performance?
A: Zings ‘Gas Gauges’ give performance for the last 8
seconds for Input and Output traffic. Placing the mouse over the gauges will give the
Average Performance since Zing was loaded (A=) and the Average Window Performance (WA=)
after about 1 second.
Q14: What sort of
performance should I get from my ZyTrax Router?
A: This depends on a lot of variables, but we have benchmarked the
router at over 15.7K bytes per second in both directions simultaneously (over 31.4K
throughput). The actual performance you can achieve depends on a number of factors:
- The speed of the end system you are
connected to (web sites, FTP sites etc.)
- Network congestion and delays.
- The performance of the Access Router you are connected to.
- The fragmentation strategy of the Access Router you are
connected to.
- The Speed and Performance of your PC.
Q15: What do you
mean by the Access Router Fragmentation strategy?
A: The MPPP (Multi-Link Point to Point Protocol) specification
allows for fragmentation of blocks when sending across a ‘bundle’ of links. Some
Access Routers fragment all blocks of greater than 100 or so bytes into fragments in the
mistaken belief that this allows load balancing. In practice it has a negative impact on
average loads consuming CPU resources unnecessarily at both ends of the link. Ask your ISP
to configure the access router to use fragmentation only when blocks are larger than the
MRRU (Maximum Receive Unit) for the link (your ZyTrax Router defaults to 1518 bytes). The
total impact on performance of excessive fragmentation is 1 – 2%. Not a lot but you
are paying for it!
Q16: I want to
monitor Microsoft’s web site www.microsoft.com
but it does not respond to pings? (always times out)
A: Certain very popular sites do not respond to ping traffic in
order to reduce loads on their systems, (Microsoft among many others does this). If your
intention is to monitor any of these sites you cannot do it, but if you intention is to
see the performance of the Route to these sites set the Target IP address to the IP
address immediately before the site you are interested in.
Q17: What is the
Window Average (WA) in Zing?
A: Zing uses a ‘Sliding Window’ of 10 times the current
Network Probe timer. The default Network Probe Time is 60 seconds, giving a default window
of 10 x 60 = 600 sec. or 10 minutes. The window period is designed to reflect the current
traffic pattern (a moving or 'short-term' average) rather that the overall ('long-term') average since Zing was loaded.
Q18: Can I log
Zing data to disc and review later?
A: Zing has a logging facility which is turned on
by clicking ‘Info’ then selecting ‘Log (Auto)’ or ‘Log
(User)’ from the ‘Options’ menu. Log(Auto) opens and Appends data to the
file ‘Zing for HotPools.txt’ in the
directory from which Zing was loaded (by default c:\Program files\zytrax\zing. Log (User)
allows you to choose the filename and location for the log file. In all cases the log file
can be read by a standard text editor such as Notepad.
Q19: Can I monitor my connection time (Bytes or Packets transferred) using Zing?
A:From version 2.0 of Zing and from version 69 of the Router application using 'Info', Statistics -> User Stats Zing will display the following statistics:
- User Name
- Date of Last Reset
- Total time Connected since last reset
- Bytes In since last reset
- Bytes Out since last reset
- Packets In since last reset
- Packets Out since last reset
- Maximum Speed of Link
- Directory Numbers of the remote service
You can reset the counts with the Reset button provided (Resets
Connection time, Bytes In & Out, Packets In & Out and updates the Reset Date after logging to Log (Auto) file.).
NOTE: You must have an active connection to do this (at least one of the B Channel indicators must be Green). If either there is no connection or version 69 (or greater) of the application is not loaded the User Stats menu entry will be disabled (grayed out).
Q20: I am having problems running ZING (gives incorrect or strange results)
A:Zing is written in Microsoft Visual Basic Version 6. It is possible that some of your system files are corrupt or out of date. You should obtain the latest versions of these files from Microsoft (Knowledge Base Article Number Q192461). To obtain the latest files proceed as follows:
- Load your browser
- Go the microsoft support Site http://support.microsoft.com
- In the 'Knowledge Base Search' Frame
- In Question 1 select 'Visual Basic'
- In Question 2 click 'Specific Article ID number'
- In box 3 enter Q192461
- Click 'Go'
- This will display a single entry - click on this entry to go to the article.
- In the 'More Information' section you will find a reference to 'vbrun60.exe' clicking this will download the updated files.
- Follow the instructions to perform the update.
NOTE: You should unload ZING prior to performing the update above.
Problems, comments, suggestions, corrections (including broken links) or something to add? Please take the time from a busy life to 'mail us' (at top of screen), the webmaster (below) or info-support at zytrax. You will have a warm inner glow for the rest of the day.
