| Author |
Message |
ns
Guest
|
 Posted:
Tue Dec 14, 2004 11:03 pm Post subject:
Ping slow on serial interface |
|
|
Hi all,
i have two cisco router serie 1700 connected by serial link (193 KBytes/s or
1544 Kbits).
The speed access to the remote router seem to be slow. For exemple, when i
lunch ping, the response is slow...
=================================================================
MyRouterA#ping ip
Target IP address: 192.168.1.2
Repeat count [5]: 30
Datagram size [100]: 1500
Timeout in seconds [2]:
Extended commands [n]:
Sweep range of sizes [n]:
Type escape sequence to abort.
Sending 30, 1500-byte ICMP Echos to 192.168.1.2, timeout is 2 seconds:
!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!
Success rate is 100 percent (30/30), round-trip min/avg/max = 180/182/184 ms
MyRouterA#
=================================================================
The serial configuration of my router (MyRouterA) is :
interface Serial0
ip address 192.168.1.1 255.255.255.252
==================================
i added commande "bandwidth=1544" but i have the same problem.
i confirm that's the bandwidth is not saturated, i juste have 3% utilization
of 193 Kbytes
Can you tell me what's i need to do please ?
ThankYou very much for your help
Best Regadrs
NS |
|
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|
 |
Arnold Nipper
Guest
|
| Posted:
Tue Dec 14, 2004 11:29 pm Post subject:
Re: Ping slow on serial interface |
|
|
On 14.12.2004 19:03 ns wrote
| Quote: | Hi all,
i have two cisco router serie 1700 connected by serial link (193 KBytes/s or
1544 Kbits).
The speed access to the remote router seem to be slow. For exemple, when i
lunch ping, the response is slow...
Can you tell me what's i need to do please ?
|
Tell us how far away the other end is (YourRouterB). While 180ms is
pretty ok when you are in NYC and YourRouterB is in Hongkong, this does
not longer hold if you have connected both routers back to back.
--
Arnold Nipper, AN45 |
|
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|
|
Erik Freitag
Guest
|
| Posted:
Tue Dec 14, 2004 11:39 pm Post subject:
Re: Ping slow on serial interface |
|
|
On Tue, 14 Dec 2004 19:03:34 +0100, ns wrote:
| Quote: | Hi all,
i have two cisco router serie 1700 connected by serial link (193 KBytes/s or
1544 Kbits).
The speed access to the remote router seem to be slow. For exemple, when i
lunch ping, the response is slow...
=================================================================
MyRouterA#ping ip
Target IP address: 192.168.1.2
Repeat count [5]: 30
Datagram size [100]: 1500
Timeout in seconds [2]:
Extended commands [n]:
Sweep range of sizes [n]:
Type escape sequence to abort.
Sending 30, 1500-byte ICMP Echos to 192.168.1.2, timeout is 2 seconds:
!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!
Success rate is 100 percent (30/30), round-trip min/avg/max = 180/182/184 ms
MyRouterA#
=================================================================
The serial configuration of my router (MyRouterA) is :
interface Serial0
ip address 192.168.1.1 255.255.255.252
==================================
i added commande "bandwidth=1544" but i have the same problem.
i confirm that's the bandwidth is not saturated, i juste have 3% utilization
of 193 Kbytes
Can you tell me what's i need to do please ?
|
How far apart are these routers? Ping times reflect latency, not bandwidth
(usually). If you do a show interface serial 0 (or whatever the serial is
called), what is the delay shown? Look for DLY 20000 usec, or something
like that. What kind of circuit connects them? PRI? Frame Relay?
Point-to-Point? The bandwidth setting is used by routing protocols and
some network management tools, but does not affect your line speed or
latency. |
|
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|
|
Phillip Remaker
Guest
|
| Posted:
Wed Dec 15, 2004 4:12 am Post subject:
Re: Ping slow on serial interface |
|
|
At size 1500, shances are you are fragmenting packets, andc fragmenting
kills performance.
Try 1400, or whatever the max is for your medium.
In the extended commands, ask to set the DF (Don't Fragment) bit to probe
for the max value. |
|
| Back to top |
|
|
Toby
Guest
|
| Posted:
Wed Dec 15, 2004 4:25 am Post subject:
Re: Ping slow on serial interface |
|
|
"ns" <ns@none.ns> wrote in message news:328o7mF3ght9iU1@individual.net...
| Quote: | Hi all,
i have two cisco router serie 1700 connected by serial link (193 KBytes/s
or
1544 Kbits).
The speed access to the remote router seem to be slow. For exemple, when i
lunch ping, the response is slow...
=================================================================
MyRouterA#ping ip
Target IP address: 192.168.1.2
Repeat count [5]: 30
Datagram size [100]: 1500
Timeout in seconds [2]:
Extended commands [n]:
Sweep range of sizes [n]:
Type escape sequence to abort.
Sending 30, 1500-byte ICMP Echos to 192.168.1.2, timeout is 2 seconds:
!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!
Success rate is 100 percent (30/30), round-trip min/avg/max = 180/182/184
ms
MyRouterA#
=================================================================
The serial configuration of my router (MyRouterA) is :
interface Serial0
ip address 192.168.1.1 255.255.255.252
==================================
i added commande "bandwidth=1544" but i have the same problem.
i confirm that's the bandwidth is not saturated, i juste have 3%
utilization
of 193 Kbytes
Can you tell me what's i need to do please ?
ThankYou very much for your help
Best Regadrs
NS
Hi |
From your config (what you have provided) I can see that you are just
pinging the remote end of your point to point connection so have no other
layer3 (IP) nodes in between.
The speed the signal travels depends on what it is travelling through but
usually can be thought of as 70% of the speed of light through a vacuum
(dont quote me on this figure as it is your problem so I have not googled
it, thats your job). The speed of light in a vacuum though is approx
300,000km/sec at 70% speed it would equate to 210,000km. So in 180ms the
distance travelled would be 5.xx times round the earth.
I dont think your connection is this long so if you are 100% sure you have
no queueing due to congestion (you state 3% utilistation) then there must be
other devices in the path between your 2 routers at layer2, (frame relay/ATM
etc) the bandwidth on these devices will be shared with other users and you
will get switching/queing delays adding to the overall delay.
N.B. most Cisco routers default to an average of traffic over 5 minutes (300
seconds) and can be configured to read an average over 30 seconds, so please
ensure you are reading your utilisation correctly.
If you are 100% sure then
Contact your service provider to establish what technology is being offered
and what service level agreement in regards to delay when your bandwidth is
in contract is being offered for the destination you are connected to.
Just to clarify. If you had a dedicated point-point link between site A and
site B your data would travel at about 70% speed of light once allowed onto
the link. (bandwidth is a mesurement of what is allowed/able to enter the
link per second and not how quick it travels in the link). So 184ms would be
5.xx times the circumrence of the world. On a dedicated point-point link the
data you sent would not have a coffee break so would not be slowed down.
This indicates you have NOT got a dedicated point to point link. If you did
have a p-p link 5 times the circumfrence of the earth you would be paying
approx $5,000,000 per month for it (figure made up for explanation purposes
only).
As it is clear you have not got a dedicated p-p link here you will be going
through a shared medium such as frame relay/ATM, the problem could be either
of the following.
1) queing delays in your providers network (as well as
switching/serialisation and the propogation (distance) delays already spoken
about), although queuing/propogation delays are the main factor here. See my
note above about contacting your service provider for your expectations.
2) the remote site Router B may have a problem with utilisation on it's link
from the service provider. i.e. your company may have many other sites
connecting with site B and although site A only has 3% util site B might be
nearing capacity. (I include this as you have no mention of this sites
config/util)
So if site A's link is only 3% util and you can clarify that site B is also
only 3% util with no other traffic then you will need to clarify your
service contract with your provider as there are delays in the service
providers network.
Toby |
|
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|
|
Arnold Nipper
Guest
|
| Posted:
Wed Dec 15, 2004 4:25 am Post subject:
Re: Ping slow on serial interface |
|
|
On 15.12.2004 00:36 Toby wrote
| Quote: | The speed the signal travels depends on what it is travelling through but
usually can be thought of as 70% of the speed of light through a vacuum
(dont quote me on this figure as it is your problem so I have not googled
it, thats your job). The speed of light in a vacuum though is approx
300,000km/sec at 70% speed it would equate to 210,000km. So in 180ms the
distance travelled would be 5.xx times round the earth.
|
If the signal travels with 210,000 km/s and if you see a RTT of 180ms,
the distance to B-Router is 210,000 * 0.18 / 2 which gives 18,900km.
This is less than half time round the earth on a great circle.
When I do a traceroute from here (Heidelberg, Germany) 180ms RTT
typically means something on the US westcoast, 100ms - 120ms is US
eastcoast, APA is something like 300ms.
Please also bear in mind that it takes some time to serialize the
packet. On slow links and with large packetsize this takes a non
negligable amount of time.
Arnold
--
Arnold Nipper, AN45 |
|
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|
|
Erik Freitag
Guest
|
| Posted:
Wed Dec 15, 2004 10:57 am Post subject:
Re: Ping slow on serial interface |
|
|
On Tue, 14 Dec 2004 23:36:06 +0000, Toby wrote:
| Quote: | Just to clarify. If you had a dedicated point-point link between site A and
site B your data would travel at about 70% speed of light once allowed onto
the link. (bandwidth is a mesurement of what is allowed/able to enter the
link per second and not how quick it travels in the link). So 184ms would be
5.xx times the circumrence of the world. On a dedicated point-point link the
data you sent would not have a coffee break so would not be slowed down.
This indicates you have NOT got a dedicated point to point link. If you did
have a p-p link 5 times the circumfrence of the earth you would be paying
approx $5,000,000 per month for it (figure made up for explanation purposes
only).
|
Just to clarify further, the speed of light in fiber is around 2/3 the
speed of light in a vacuum, or around 200000 km/s. Ping time is 184 ms so
a one-way trip is around 92 ms. 200000 km/s = 124300 mi/s = 124.3 mi/ms or
10192 miles. This is possible on my planet, just a little more than the
great circle distance from London to Tokyo. |
|
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|
|
Jonathan
Guest
|
| Posted:
Wed Dec 15, 2004 2:52 pm Post subject:
Re: Ping slow on serial interface |
|
|
"ns" <ns@none.ns> wrote in message news:328o7mF3ght9iU1@individual.net...
| Quote: | Hi all,
i have two cisco router serie 1700 connected by serial link (193 KBytes/s
or
1544 Kbits).
The speed access to the remote router seem to be slow. For exemple, when i
lunch ping, the response is slow...
=================================================================
MyRouterA#ping ip
Target IP address: 192.168.1.2
Repeat count [5]: 30
Datagram size [100]: 1500
Timeout in seconds [2]:
Extended commands [n]:
Sweep range of sizes [n]:
Type escape sequence to abort.
Sending 30, 1500-byte ICMP Echos to 192.168.1.2, timeout is 2 seconds:
!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!
Success rate is 100 percent (30/30), round-trip min/avg/max = 180/182/184
ms
MyRouterA#
|
What's wrong with the ping time?
This is pretty decent for a 1500 byte ping.
=================================================================
| Quote: | The serial configuration of my router (MyRouterA) is :
interface Serial0
ip address 192.168.1.1 255.255.255.252
==================================
i added commande "bandwidth=1544" but i have the same problem.
|
Because that command is the default (well, 'bandwidth 1536' is), and it is
only used so EIGRP can accurately calculate its metric.
| Quote: | i confirm that's the bandwidth is not saturated, i juste have 3%
utilization
of 193 Kbytes
Can you tell me what's i need to do please ?
|
Nothing.
Jonathan |
|
| Back to top |
|
|
Jonathan
Guest
|
| Posted:
Wed Dec 15, 2004 2:57 pm Post subject:
Re: Ping slow on serial interface |
|
|
"Toby" <Nomail@ntlworld.com> wrote in message
news:GNKvd.317$876.220@newsfe3-gui.ntli.net...
| Quote: |
"ns" <ns@none.ns> wrote in message news:328o7mF3ght9iU1@individual.net...
Hi all,
i have two cisco router serie 1700 connected by serial link (193 KBytes/s
or
1544 Kbits).
The speed access to the remote router seem to be slow. For exemple, when
i
lunch ping, the response is slow...
=================================================================
MyRouterA#ping ip
Target IP address: 192.168.1.2
Repeat count [5]: 30
Datagram size [100]: 1500
Timeout in seconds [2]:
Extended commands [n]:
Sweep range of sizes [n]:
Type escape sequence to abort.
Sending 30, 1500-byte ICMP Echos to 192.168.1.2, timeout is 2 seconds:
!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!
Success rate is 100 percent (30/30), round-trip min/avg/max = 180/182/184
ms
MyRouterA#
=================================================================
The serial configuration of my router (MyRouterA) is :
interface Serial0
ip address 192.168.1.1 255.255.255.252
==================================
i added commande "bandwidth=1544" but i have the same problem.
i confirm that's the bandwidth is not saturated, i juste have 3%
utilization
of 193 Kbytes
Can you tell me what's i need to do please ?
ThankYou very much for your help
Best Regadrs
NS
Hi
From your config (what you have provided) I can see that you are just
pinging the remote end of your point to point connection so have no other
layer3 (IP) nodes in between.
The speed the signal travels depends on what it is travelling through but
usually can be thought of as 70% of the speed of light through a vacuum
(dont quote me on this figure as it is your problem so I have not googled
it, thats your job). The speed of light in a vacuum though is approx
300,000km/sec at 70% speed it would equate to 210,000km. So in 180ms the
distance travelled would be 5.xx times round the earth.
|
Which doesn't account for encapsulation, serialization delays, frame-relay
switch latency, and FRATM latency.
There is nothing wrong with his ping times.
| Quote: | I dont think your connection is this long so if you are 100% sure you have
no queueing due to congestion (you state 3% utilistation) then there must
be other devices in the path between your 2 routers at layer2, (frame
relay/ATM etc) the bandwidth on these devices will be shared with other
users and you will get switching/queing delays adding to the overall
delay.
N.B. most Cisco routers default to an average of traffic over 5 minutes
(300 seconds) and can be configured to read an average over 30 seconds, so
please ensure you are reading your utilisation correctly.
If you are 100% sure then
Contact your service provider to establish what technology is being
offered and what service level agreement in regards to delay when your
bandwidth is in contract is being offered for the destination you are
connected to.
|
The SLA for telcos is 120ms for a 100-byte packet, end to end from our
ingress switches.
He is getting about 45% higher ping times for 1400% more data being sent. He
needs to calm down.
Jonathan |
|
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|
|
ns
Guest
|
| Posted:
Wed Dec 15, 2004 4:48 pm Post subject:
Re: Ping slow on serial interface |
|
|
MyRouterA is located at Paris
MyRouterB is located at San Francisco
"Arnold Nipper" <arnold-200411@nipper.de> a écrit dans le message de
news:cpnbdm$oah$1@nntp.ilk.net...
| Quote: | On 14.12.2004 19:03 ns wrote
Hi all,
i have two cisco router serie 1700 connected by serial link (193
KBytes/s or
1544 Kbits).
The speed access to the remote router seem to be slow. For exemple, when
i
lunch ping, the response is slow...
Can you tell me what's i need to do please ?
Tell us how far away the other end is (YourRouterB). While 180ms is
pretty ok when you are in NYC and YourRouterB is in Hongkong, this does
not longer hold if you have connected both routers back to back.
--
Arnold Nipper, AN45 |
|
|
| Back to top |
|
|
ns
Guest
|
| Posted:
Wed Dec 15, 2004 4:54 pm Post subject:
Re: Ping slow on serial interface |
|
|
DLY = 20000 usec
Circuit : PPP
more informations a bout serial interface
======================================================
MyRouterA#sh int s0
Serial0 is up, line protocol is up
Hardware is PowerQUICC Serial
Internet address is 192.168.25.10/30
MTU 1500 bytes, BW 1544 Kbit, DLY 20000 usec,
reliability 255/255, txload 1/255, rxload 1/255
Encapsulation HDLC, loopback not set
Keepalive set (10 sec)
Last input 00:00:03, output 00:00:00, output hang never
Last clearing of "show interface" counters 4d19h
Input queue: 0/75/0/0 (size/max/drops/flushes); Total output drops: 16
Queueing strategy: weighted fair
Output queue: 0/1000/64/16 (size/max total/threshold/drops)
Conversations 0/13/256 (active/max active/max total)
Reserved Conversations 0/0 (allocated/max allocated)
Available Bandwidth 1158 kilobits/sec
======================================================
Thanks a lot
NS
| Quote: | How far apart are these routers? Ping times reflect latency, not bandwidth
(usually). If you do a show interface serial 0 (or whatever the serial is
called), what is the delay shown? Look for DLY 20000 usec, or something
like that. What kind of circuit connects them? PRI? Frame Relay?
Point-to-Point? The bandwidth setting is used by routing protocols and
some network management tools, but does not affect your line speed or
latency. |
|
|
| Back to top |
|
|
ns
Guest
|
| Posted:
Wed Dec 15, 2004 4:58 pm Post subject:
Re: Ping slow on serial interface |
|
|
I tested with default datagram size (100), 1400 and 1500 and i have the same
result.
I tested with option "Set DF bit in IP header? [no]: yes" and i have the
same result
Thank You very much
NS
"Phillip Remaker" <remaker@cisco.com> a écrit dans le message de
news:1103066228.357650@sj-nntpcache-3...
| Quote: | At size 1500, shances are you are fragmenting packets, andc fragmenting
kills performance.
Try 1400, or whatever the max is for your medium.
In the extended commands, ask to set the DF (Don't Fragment) bit to probe
for the max value.
|
|
|
| Back to top |
|
|
ns
Guest
|
| Posted:
Wed Dec 15, 2004 5:13 pm Post subject:
Re: Ping slow on serial interface |
|
|
| Quote: | From your config (what you have provided) I can see that you are just
pinging the remote end of your point to point connection so have no other
layer3 (IP) nodes in between.
|
Yes, exactly
| Quote: |
The speed the signal travels depends on what it is travelling through but
usually can be thought of as 70% of the speed of light through a vacuum
(dont quote me on this figure as it is your problem so I have not googled
it, thats your job). The speed of light in a vacuum though is approx
300,000km/sec at 70% speed it would equate to 210,000km. So in 180ms the
distance travelled would be 5.xx times round the earth.
I dont think your connection is this long so if you are 100% sure you have
no queueing due to congestion (you state 3% utilistation) then there must
be
other devices in the path between your 2 routers at layer2, (frame
relay/ATM
etc) the bandwidth on these devices will be shared with other users and
you
will get switching/queing delays adding to the overall delay.
N.B. most Cisco routers default to an average of traffic over 5 minutes
(300
seconds) and can be configured to read an average over 30 seconds, so
please
ensure you are reading your utilisation correctly.
If you are 100% sure then
Contact your service provider to establish what technology is being
offered
and what service level agreement in regards to delay when your bandwidth
is
in contract is being offered for the destination you are connected to.
Just to clarify. If you had a dedicated point-point link between site A
and
site B your data would travel at about 70% speed of light once allowed
onto
the link. (bandwidth is a mesurement of what is allowed/able to enter the
link per second and not how quick it travels in the link). So 184ms would
be
5.xx times the circumrence of the world. On a dedicated point-point link
the
data you sent would not have a coffee break so would not be slowed down.
This indicates you have NOT got a dedicated point to point link. If you
did
have a p-p link 5 times the circumfrence of the earth you would be paying
approx $5,000,000 per month for it (figure made up for explanation
purposes
only).
|
:)
| Quote: |
As it is clear you have not got a dedicated p-p link here you will be
going
through a shared medium such as frame relay/ATM, the problem could be
either
of the following.
1) queing delays in your providers network (as well as
switching/serialisation and the propogation (distance) delays already
spoken
about), although queuing/propogation delays are the main factor here. See
my
note above about contacting your service provider for your expectations.
2) the remote site Router B may have a problem with utilisation on it's
link
from the service provider. i.e. your company may have many other sites
connecting with site B and although site A only has 3% util site B might
be
nearing capacity. (I include this as you have no mention of this sites
config/util)
So if site A's link is only 3% util and you can clarify that site B is
also
only 3% util with no other traffic then you will need to clarify your
service contract with your provider as there are delays in the service
providers network.
Toby
|
ThankYou very much for your answer
NS |
|
| Back to top |
|
|
ns
Guest
|
| Posted:
Wed Dec 15, 2004 5:20 pm Post subject:
Re: Ping slow on serial interface |
|
|
| Quote: |
What's wrong with the ping time?
This is pretty decent for a 1500 byte ping.
|
i have the same result when i test with small packet
For exemple :
=============================================================
MyRouterA#ping ip
Target IP address: 192.168.1.2
Repeat count [5]: 30
Datagram size [100]:
Timeout in seconds [2]:
Extended commands [n]:
Sweep range of sizes [n]:
Type escape sequence to abort.
Sending 30, 100-byte ICMP Echos to 192.168.1.2, timeout is 2 seconds:
!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!
Success rate is 100 percent (30/30), round-trip min/avg/max = 164/166/168 ms
=============================================================
it's too late !!
|
|
| Back to top |
|
|
Barry Margolin
Guest
|
| Posted:
Wed Dec 15, 2004 5:43 pm Post subject:
Re: Ping slow on serial interface |
|
|
In article <32amksF3jf315U1@individual.net>, "ns" <ns@none.ns> wrote:
| Quote: | MyRouterA is located at Paris
MyRouterB is located at San Francisco
|
Your packets have to travel 6,000 miles and you think 180 ms is slow?
You'll get a speeding ticket if you try to exceed the speed of light.
--
Barry Margolin, barmar@alum.mit.edu
Arlington, MA |
|
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|
|
|
|
|
|
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