QoS Questions for 3750 Switches

2x3750 switches are stacked and we are trying to simulate traffic congestion at the UTP ports by using Smartbit 6000C. The objective of the test is to see if the QoS setting works in reality even though we see from Wireshark that the packets are marked with DSCP for voice traffic.
Setup is as follows :
Smartbit<->Avaya IP Phone<->3750 switches<->6509 switch.
Please note that the configuration is set on the 3750 switch port as well as trusted on the Cat 6 switch port. However, when I set to continuous traffic with byte size of 64. Even though its a 100Mbps port, the Avaya IP Phone is already acting weird with hanged symptom. Just side note is that performing "show mls qos inter gi2/0/7 statistic" shows that data and voice traffic are marked on the different priority which seemed correct.
1) Is this the right way to test? If not, what should be the correct way?
2) The port that's connected to Smartbit is configured and it seemed that with the continuous traffic, even other IP Phones are hanged even though I have set Smartbit to hit on the IP address of the CAT6 Switch port. This is not normal right as this is supposed to be unicast traffic. Any idea what could be the reason?

Hello Brandon,
I understand your concern and how you want to test, but with the VoIP services you need to understand that there are 2 points (telephones if you want) involved. Your local one, where you might have taken all the necessary steps to protect and prioritize your voice traffic, and the oposite end which also need to have the voice packets prioritized.
Now, from your description, I understand that the packets (voice and data) marked correctly (I believe on C3750), but that's not enough. You need to use CBWFQ together with LLQ to give priority to the Voice traffic over data in case of congestion. Do you have such configuration? Can you show us some excerpt from it?
Next, during the testing, you said that your phone hang-up...where you in a call?
To respond to your questions:
1. The start is ok, but we need more details. You are pushing traffic from Smarbit, this is your local end, but where is the traffic pushed to (remote end), who is receiving the traffic?
2. In theory, you shouldn't have any impact over voice if links are 100Mbit, only if you have such a power packet generator that could fill 100Mbit. What do you mean by "This is not normal right as this is supposed to be unicast traffic"? VoIP is also unicast traffic...
I can see that you are determined to solve this issue, and this is OK as it will help you back with gained knowledge, but I have to warn you that troubleshooting QoS / Voice related problems may be more tricky than you think, as it will involve a strong know-how in these areas.
We will help, but you have to come back with more precise details.
Good luck!
Calin

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Snmp for 3750 switch stack

Hi,
I have two 3750 switch stack together with one ip address mange the stack.
Can I monitor the memory and cpu for each individual switch? what is the oid then?
Thanks.
C.K.

Hello CK,
On the Catalyst 3750, the stack master handles the SNMP requests and traps for the whole switch stack.
The stack master transparently manages any requests or traps that are related to all stack members. When a new stack master is elected, the new master continues to handle SNMP requests and traps as configured on the previous stack master, assuming that IP connectivity to the SNMP management stations is still in place after the new master has taken control.
So to answer your question, with the OID for CPU and Mempory usage the switch will return only values for the active master. The other stack members are hot standby and do not produce SNMP information for CPU and/or Memory.
HTH
--Leon

Best IOS version for 3750 switch

I have just received 2 3750 switches, but both have a different IOS version.
One has -> IOS version 12.1(19)EA1d
and the other has -> IOS version 12.2(25)SEB2.
I just want to use the switches as Gb collectors for a serverfarm seperatly (so no stack configuration) with a redundant uplink to my distribution layer.
Can someone advise my which IOS is the best for my network?
Thanx, Marty

Switch 1:
Cisco Internetwork Operating System Software
IOS (tm) C3750 Software (C3750-I5-M), Version 12.1(19)EA1d, RELEASE SOFTWARE (fc1)
Copyright (c) 1986-2004 by cisco Systems, Inc.
Compiled Mon 05-Apr-04 22:06 by antonino
Image text-base: 0x00003000, data-base: 0x009206D8
ROM: Bootstrap program is C3750 boot loader
BOOTLDR: C3750 Boot Loader (C3750-HBOOT-M) Version 12.1(14r)EA1a, RELEASE SOFTWARE (fc1)
2224-3750-037000137 uptime is 23 hours, 52 minutes
System returned to ROM by power-on
System restarted at 09:02:42 GMT Thu Aug 11 2005
System image file is "flash:c3750-i5-mz.121-19.EA1d/c3750-i5-mz.121-19.EA1d.bin"
cisco WS-C3750G-24TS (PowerPC405) processor (revision H0) with 118776K/12288K bytes of memory.
Processor board ID CAT0904X00B
Last reset from power-on
Bridging software.
1 Virtual Ethernet/IEEE 802.3 interface(s)
28 Gigabit Ethernet/IEEE 802.3 interface(s)
The password-recovery mechanism is enabled.
512K bytes of flash-simulated non-volatile configuration memory.
Base ethernet MAC Address : 00:13:1A:65:50:00
Motherboard assembly number : 73-7058-12
Power supply part number : 341-0045-01
Motherboard serial number : CAT090400A0
Power supply serial number : LIT09020266
Model revision number : H0
Motherboard revision number : A0
Model number : WS-C3750G-24TS-E
System serial number : CAT0904X00B
Hardware Board Revision Number : 0x09
Switch Ports Model SW Version SW Image
* 1 28 WS-C3750G-24TS 12.1(19)EA1d C3750-I5-M
Configuration register is 0xF
Switch 2:
Cisco IOS Software, C3750 Software (C3750-IPSERVICES-M), Version 12.2(25)SEB2, RELEASE SOFTWARE (fc1)
Copyright (c) 1986-2005 by Cisco Systems, Inc.
Compiled Wed 08-Jun-05 01:19 by yenanh
ROM: Bootstrap program is C3750 boot loader
BOOTLDR: C3750 Boot Loader (C3750-HBOOT-M) Version 12.1(14r)EA1a, RELEASE SOFTWARE (fc1)
2224-3750-037000138 uptime is 59 minutes
System returned to ROM by power-on
System image file is "flash:c3750-ipservices-mz.122-25.SEB2/c3750-ipservices-mz.122-25.SEB2.bin"
cisco WS-C3750G-24TS (PowerPC405) processor (revision L0) with 118784K/12280K bytes of memory.
Processor board ID CAT0925Z0WZ
Last reset from power-on
1 Virtual Ethernet interface
28 Gigabit Ethernet interfaces
The password-recovery mechanism is enabled.
512K bytes of flash-simulated non-volatile configuration memory.
Base ethernet MAC Address : 00:14:A8:71:CA:00
Motherboard assembly number : 73-7058-13
Power supply part number : 341-0045-01
Motherboard serial number : CAT09251J90
Power supply serial number : PHI09220165
Model revision number : L0
Motherboard revision number : A0
Model number : WS-C3750G-24TS-E
System serial number : CAT0925Z0WZ
Hardware Board Revision Number : 0x09
Switch Ports Model SW Version SW Image
* 1 28 WS-C3750G-24TS 12.2(25)SEB2 C3750-IPSERVICES-M
Configuration register is 0xF

WAAS Configuration for 3750 Switch

I am configuring a 3750 switch with 12.2(52)SE according to:
(from https://www.cisco.com/en/US/docs/switches/lan/catalyst3750/software/release/12.2_52_se/configuration/guide/3750_scg.pdf )
This example shows how to configure SVIs and how to enable the web cache service with a multicast group list. VLAN 299 is created and configured with an IP address of 175.20.20.10. Gigabit Ethernet port 1 is connected through the Internet to the web server and is configured as an access port in VLAN 299. VLAN 300 is created and configured with an IP address of 172.20.10.30. Gigabit Ethernet port 2 is connected to the application engine and is configured as an access port in VLAN 300. VLAN 301 is created and configured with an IP address of 175.20.30.50. Fast Ethernet ports 3 to 6, which are connected to the clients, are configured as access ports in VLAN 301. The switch redirects packets received from the client interfaces to the application engine.
Note Only permit ACL entries are being used in the redirect-list; deny entries are unsupported.
Switch# configure terminal
Switch(config)# ip wccp web-cache 80 group-list 15
Switch(config)# access-list 15 permit host 171.69.198.102
Switch(config)# access-list 15 permit host 171.69.198.104
Switch(config)# access-list 15 permit host 171.69.198.106
Switch(config)# vlan 299 WEB SERVER
Switch(config-vlan)# exit
Switch(config)# interface vlan 299
Switch(config-if)# ip address 175.20.20.10 255.255.255.0
Switch(config-if)# exit
Switch(config)# interface gigabitethernet1/0/1
Switch(config-if)# switchport mode access
Switch(config-if)# switchport access vlan 299
Switch(config)# vlan 300 WAE
Switch(config-vlan)# exit
Switch(config)# interface vlan 300
Switch(config-if)# ip address 171.69.198.100 255.255.255.0
Switch(config-if)# exit
Switch(config)# interface gigabitethernet1/0/2
Switch(config-if)# switchport mode access
Switch(config-if)# switchport access vlan 300
Switch(config-if)# exit
Switch(config)# vlan 301 CLIENTS
Switch(config-vlan)# exit
Switch(config)# interface vlan 301
Switch(config-if)# ip address 175.20.30.20 255.255.255.0
Switch(config-if)# ip wccp web-cache redirect in
Switch(config-if)# exit
Switch(config)# interface gigabitethernet1/0/3 - 6
Switch(config-if-range)# switchport mode access
Switch(config-if-range)# switchport access vlan 301
Switch(config-if-range)# exit
===================================================================
Question: How do I configure my WAE to play nicely with this switch?

Hi James,
Here is the link to WCCP config part on WAE:
http://www.cisco.com/en/US/docs/app_ntwk_services/waas/waas/v441/configuration/guide/traffic.html#wp1041742
In your case, if my understanding is right, VLAN300 is where you want to connect WAE and WAE is also L2 adjacent. if that is true, here is the config you need on WAE:
wccp router-list 1 171.69.198.100
wccp tcp-promiscuous router-list-num 1 l2-redirect mask-assign l2-return
wccp version 2
Please note that 3750 supports L2 redirection only with redirect IN statements on 3750 interfaces connected to servers and clients.
Hope this helps.
Regards.

Using 3750 switches & 2821 router for video & http qos

Hello all,
I know that the 3750 switches and 2821 routers are aging platforms, though, was curious if it they are capable of providing QoS for video (such as WebEx) and HTTP/HTTPS, in addition to voice traffic?
Thanks

Thank you Reza.
One reason we're looking into this, is that we wanted to see if we could give priority to traffic destined for, and arriving from, certain servers (in addition to certain classes of traffic). Is that possible? Most of our switches have IPBase images (12.2(55)SE1).
Thanks

Questions for QoS on switches

Hello Experts,
I currently have QoS settings on my switch:
class-map match-any VOIP
match dscp cs5
match dscp ef
class-map match-all VIDEO_Conference
match dscp af41
class-map match-all ROUTING
match dscp cs6
policy-map myLAN
class VOIP
set dscp ef
class VIDEO_Conference
set dscp af41
class ROUTING
set dscp cs6
interface g1/1
ip address 10.10.12.1 255.255.255.0
ip pim sparse-mode
service-policy input myLAN
service-policy output myLAN
I understand that the class-map is for defining the traffic and policy-map is for creating policy for the map traffic. But still confusing the ways they're working.
For this example:
class-map match-any VOIP
match dscp cs5
match dscp ef
How do i know that VOIP packet is cs5/ef? are there any predefined info for VOIP packets? what are cs5 and ef really playing the roles here?
Thanks.

Hi,
Thanks for the reply, for this CS5 again:
class-map match-any VOIP
match dscp cs5
match dscp ef
I've checked from my switch:
Switch(config-cmap)#match dscp ?
<0-63> Differentiated services codepoint value
af11 Match packets with AF11 dscp (001010)
af12 Match packets with AF12 dscp (001100)
af13 Match packets with AF13 dscp (001110)
af21 Match packets with AF21 dscp (010010)
af22 Match packets with AF22 dscp (010100)
af23 Match packets with AF23 dscp (010110)
af31 Match packets with AF31 dscp (011010)
af32 Match packets with AF32 dscp (011100)
af33 Match packets with AF33 dscp (011110)
af41 Match packets with AF41 dscp (100010)
af42 Match packets with AF42 dscp (100100)
af43 Match packets with AF43 dscp (100110)
cs1 Match packets with CS1(precedence 1) dscp (001000)
cs2 Match packets with CS2(precedence 2) dscp (010000)
cs3 Match packets with CS3(precedence 3) dscp (011000)
cs4 Match packets with CS4(precedence 4) dscp (100000)
cs5 Match packets with CS5(precedence 5) dscp (101000)
cs6 Match packets with CS6(precedence 6) dscp (110000)
cs7 Match packets with CS7(precedence 7) dscp (111000)
default Match packets with default dscp (000000)
ef Match packets with EF dscp (101110)
when it says 'cs5 Match packets with CS5(precedence 5) dscp (101000)', does that mean the network packet's binary has to match this binary 101000 to able to define it as cs5?
I need to wrap my head around this QoS since i've been having a serious confusion about this QoS things. How would you explain this below in our language?
class-map match-any VOIP
match dscp cs5
match dscp ef
policy-map myLAN
class VOIP
set dscp ef
interface g1/1
ip address 10.10.12.1 255.255.255.0
ip pim sparse-mode
service-policy input myLAN
service-policy output myLAN
Thanks a lot!

Question on ARP table on 3750 switch

Hi,
So I have a cisco 3750 switch directly connected to a 2851 router gig 0/0 interface.
Should the show arp command on the switch show an entry for the IP and mac address of the routers gig 0/0 interface?
I dont see one in there now and was just wondering.
Connectivity between the switch and router work fine right now.
thanks

HI Bill,
if u can ping from Swicth ro router,,,,then please check with this command: sh ip arp.
Just for Info;
To be able to ARP a device, you must have an interface (SVI) on that switch on that network. To ARP a device you must have an interface with a layer 3 IP on the same layer 2 vlan.
You will need to connect to a switch that has an interface on that vlan on it. I would traceroute to the host, and hopefully the next to last hop is the layer 3 switch, or if it's a router, connect to it and do a show cdp neighbors and see if you can find the switch that way. (If you do connect to the router, you'll find the ARP entries there, if it's a layer 3 switch, then it's both a router and switch in one box)
"sh mac address-table". This will give which MAC is connected to which port.
"sh ip device tracking interface gigabitEthernet ". This will give which IP is connectd to a port.
"sh ip arp" will give you a IP to MAC table
Regards
Dont forget to rate helpful posts.

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Best QOS Practice for a congested Uplink Port?

I have an MPLS uplink port to a carrier that carries both voice and data.
For example, Customer 3750 Switch 100MB Uplink--->100MB Uplink Carrier Router---Carrier Router 6MB MLPP Voice/Data MPLS Uplink with QOS configured for Voice subnet on carrier side too.
The port occasionally suffers from overutilizition and spikes to the full 6MB
I have a centralized CUCM that has phones that occasionally reset due to TCP 2000 timeouts (usually during the period of high utilization)
So that I can avoid most phone resets during high utilization I have prioritized all voice traffic (signalling and RTP streams) to EF
My question: What is best practice configuration for a congested uplink port? I'm going to assume the answer is it depends (the all great technical answer )
Here are my thoughts on how to configure the 3750 uplink port so far:
apply mls qos trust dscp
apply priority-queue out
(Here's where I'm looking for help)
apply some sort of policing or bandwidth statement on the interface to protect the voice traffic: What are the recommendations and what would those configurations look like?
I would apply these these configurations to the uplink ports at the edge site as well as the central site.
Any thoughts as to the best way to accomplish this?

Disclaimer
The Author of this posting offers the information contained within this posting without consideration and with the reader's understanding that there's no implied or expressed suitability or fitness for any purpose. Information provided is for informational purposes only and should not be construed as rendering professional advice of any kind. Usage of this posting's information is solely at reader's own risk.
Liability Disclaimer
In no event shall Author be liable for any damages whatsoever (including, without limitation, damages for loss of use, data or profit) arising out of the use or inability to use the posting's information even if Author has been advised of the possibility of such damage.
Posting
You want to prioritize VoIP traffic at congestion points, which for you, looks to be whenever your LAN bandwidth hits your 6 Mbps WAN.
If the carrier takes your 100 Mbps, and doesn't just generally police all traffic to 6 Mbps, but instead has different priority queues for the 6 Mbps, all you should need to do, is insure you traffic is correctly processed by your WAN vendor. This, though, might require marking your traffic for the WAN provider.
If you carrier first polices all your traffic at 6 Mbps (many do), then you need to shape the traffic (with you own prioritization) before the provider "sees" it. If you need to "shape" on the 3750, there's a command to limit a port's bandwidth utilization, as a percentage. However it's not exact, so you may need to "shape" slower than 6 Mbps to insure 6 Mbps won't be exceeded. (BTW, for 6 Mbps, if you need to do QoS, you would be better off with an ISR.)
You also mention 6 MLPPP, but it's unlclear what your device is for that.
How to configure 3750 QoS is involved. Basically when you enable QoS, each port has four dedicated egress queues. By default, different traffic markings go into one of the four queues, each queue has same share of the bandwidth, and almost same share of the buffers. The PQ command you noted, enables the first queue to always transmit its packets first. Normally, you'll want to do that for VoIP bearer packets, which you've (insured are) directed to that queue. You also want to insure that VoIP signally packets are not likley to be dropped and, more or less, are forwarded quickly.
Cisco has multiple papers on QoS configurations, including papers for 3750s, so instead of my trying to present that, the above is intended as an overview. Feel free to post additional questions, the more specific, the more likely you'll get an answer.

QoS config for Video Traffic

Hello all,
I have a campus network with several remote sites, at the campus I have a 6509 at the core and 3560 and 3750 switches at the access layer. I do have QoS enable on the 6509 and I am using auto QoS on the 3560 and 3750 switches and all seems to be working fine with my existing VOIP environment. But now as I am in the middle of rolling out a video conferencing solution with the existing QoS config I am experiencing a noticeable delay between audio and video. Example like during a video call I can tell that the voice and the lips of the person speaking are not in synch.
Has anyone run into this issue ? can someone provide me a sample QoS config for the 6509 and 3560/3750 switches ?
P.S. I am using a Tandberg/Codian solution for video conferencing with Tandberg/Codian MCU, IP Gateway, ISDN Gateway and Tandberg endpoints. And both the endpoints and the back-end infrastructure devices and are set for IP Precedence 5.
Thank you very much in advance !!!
Danny

The main concern with configuring your back-end infrastructure devices with IP Precedence value 5 is that the 3560/3750 auto-qos will map this value to Q1 which is ordinarily the strict priority Q.
In most cases auto-qos will also configure or map Video to Q3, you can see this as a majority SRR bandwidth is assigned to the Q.
In order to use the strict priority queue, it has to be enabled on the interface 'priority-queue out', without it Q1 will not be emptied before the others. It will be serviced according to the weight.
With auto-qos Q1 will not have enough bandwidth as it will be assigned to Q3. Therefore you could initially enable priority-queue if not already enabled so that Q1 is emptied first, or you increase the weight.
The next question is whether you are using egress scheduling within the Core? and this conforms to your edge classification for Video?
HTH.
Allan

Connection of LC/APC fiber patch cords to Cisco Catalyst 6500 $ Cisco Access 3750 Switches

I have an LC/APC fiber patch cord infrastructure and I want to connect it to Cisco Catalyst 6500 & Cisco Access 3750 Switches. what type of transceiver should be used?
I read a note on Cisco website stating the following for Cisco SFP+ transceivers:
Note: "Only connections with patch cords with PC or UPC connectors are supported. Patch cords with APC connectors are not supported. All cables and cable assemblies used must be compliant with the standards specified in the standards section"

Thank you, but my question is that I have a single mode fiber patch cord with LC/APC connector while cisco stating a note that only use LC/PC or LC/UPC type of connectors with SFP+ transceiver.
So what type of transceiver should I use to connect LC/APC patch cord to cisco switches? Is there another type or SFP+ still can be used?

ISCSI traffic running across Cisco 3750 Switches

My customer has a small shop with 2 servers runnig iSCSI to a SAN device. They are looking for a switch recommendation and I would like to use a pair of Cisco 3750's, to take advantage of the VSS technology for redundancy,L3 and some other Core requirements, but I am concerned about performance.
I thought my other option is to use 3750E's but concerned about the added costs.

The fabric and pps ratings for the 3750Gs don't support wire-rate for more than 16 gig ports. (Max performance for 3750G models is 38.7 Mpps and 32 Gbps fabric; for 3750-E it's 101.2 Mpps and 128 Gbps fabric [NB: pps is enough, slightly insufficent fabric bandwidth for 48 port models - similar 4948 offers 102 Mpps, 136 Gbps].)
Another performance limitation of the 3750s (and to lessor extent the 3750-Es) is stack ring bandwidth. As best I can tell, the 32 Gbps is really dual 8 Gbps duplex (dual 16 Gbps duplex for -Es). An important distinction between the original StackWise technology and the later StackWise+, the former puts a copy of all traffic on the stack, the latter suppresses unnecessary unicast. The former also requires the sender to remove the traffic from the stack ring, the latter the destination removes the traffic. (I.e. the "+" technology, really is plus.)
For really, really demanding performance, a stack ring isn't the same as a chassis fabric (e.g. 4500s), and within a single switch, the lower end switch models, they can't always provide wire-rate for all their ports. However, the real question is whether you need this performance in a small shop even though iSCSI is being used.
In other words, its rare to see all ports demanding full bandwidth, so a stack of 48 port 3750Gs migtht work just fine for your customer if the actual need doesn't require more than the device can supply.
In similar situations, I present the customer with such facts. Based on what the expected load is, device "A" might work fine, but it can't guarantee performance beyond a certain level. If customer wants the capability for more performance, for growth or "just to be safe", can do too, here's your options (and extra cost) for that too.
BTW, if SAN devices can support 10gig, then you'll need something better than the 3750G since the model with a single 10gig port has been discontinued.

QoS Configuration for NME-AIR-WLC

Hello,
I have a question on the correct QoS configuration for a VoIP deployment. I have followed the steps referenced here but have two questions..
1) The last recommendation in the list is to set DCA channel sensitivity to High to avoid changes during business hours. I think this should be Low? The manual states "Low—The DCA algorithm is not particularly sensitive to environmental changes."
2) The recommendation is to trust dscp on AP uplinks and to trust cos on the WLC uplink. However I can't find any configuration guidelines for configuring QoS if the WLC in question is an NME hosted in a 2921.
2a) The link between the switch and the 2921 is an 802.1q trunk so should I trust cos on this link rather than dscp?
2b) What configuration should be on the 2921? Create a policy-map and apply it to the uplink port?
2c) Should there be a service policy assigned to the In1/0 interface for the WLC itself?
Any thoughts appreciated.
Thanks,
Dave

Well I appear to have answered question 2 after I stopped being lazy and did some packet captures.
No configuration required on 2921 as packets captured from In1/0 and Gi0/0 show correct DSCP markings on RTP and SCCP packets.
Would still be interested to know on question 1 though.

Looking for 3750 replacements

Hi,
We currently have 3750 switch stacks for our office LAN (6 switches in each stack). These are now end of life/support and are failing on a regular basis.
We are looking to replace them and I am just wondering what people would recommend to replace them with.
The main criteria to fulfil is there must be 1400 ports and they must be POE. I want 100Mbps ports as I dont really feel gig is required, but would like some gig options as well so I can compare the difference in price.
Any recommendations would be appreciated.
Thanks

Disclaimer
The Author of this posting offers the information contained within this posting without consideration and with the reader's understanding that there's no implied or expressed suitability or fitness for any purpose. Information provided is for informational purposes only and should not be construed as rendering professional advice of any kind. Usage of this posting's information is solely at reader's own risk.
Liability Disclaimer
In no event shall Author be liable for any damages whatsoever (including, without limitation, damages for loss of use, data or profit) arising out of the use or inability to use the posting's information even if Author has been advised of the possibility of such damage.
Posting
Nexus are oriented more for high performance in the data center. For user access, they might be much more expensive and they can (only currently?) miss some features. (We've found their QoS cannot accomplish what we routinely do on 3Ks, 4500s or 6500s.)
4500s often can be in the same price ballpark of a large(r) 3750 stack, especially when supporting full L3. Basically 4500 line cards cost less, but that's offset by other 4500 components, especially the supervisors.

Basic QoS questions

Hello,
Out company is finally going to install VOIP, they will be using something called Natterbox, but I've been asked to add QoS to our Cisco switches and routers in various locations I will also need to add a second VLAN for voice I believe which is ok.
How can we configure QoS so VOIP is treated first then video streaming then video?
As we will need to add a second VLAN, so I assum all ports to phone swill be truk ports?
Thanks

Andy,
To start, you need to understand how the soft phone and desk phones mark voice traffic. Cisco switch and Routers perform QoS by trusting, understanding or marking traffic using DSCP, PHB and port numbers.
Hence questions you need to ask are
1. Do the softphones mark their voice and video traffic? If they do how do they do it?
2. What ports are used for voice traffic?
3. what ports are used for signalling traffic
4.What ports are used for video traffic if its differs from ports used for voice.
Once these facts are understood, you can beging to look at how to configure your switches and routers based on this parameters
Please rate all useful posts
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QoS Questions for 3750 Switches

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