Questions tagged [qos]

For questions about Quality Of Service (QoS); all aspects of providing differential service to packets based on TOS, DSCP, or other information.

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votes
1answer
436 views

Traffic marking is not working properly in QoS

Traffic marking is not working properly in QoS. I have a problem with the policy map marking bit. I would like to monitor the traffic that matches the IP precedence bit 4 in Po 50, but from the ...
4
votes
6answers
648 views

Can QoS settings interfere with wireless printing? [closed]

This may seem like a rudimentary question, but I wasn't sure where else to ask it. I've set up some QoS rules on my router that give the highest priority to all traffic incoming and outgoing to my ...
4
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2answers
4k views

cisco 877 router QoS on traffic with a specific destination

Is it possible to throttle traffic coming or going to a specific ip address on a cisco 877 running : C870-ADVIPSERVICESK9-M, 12.4(15)T12, RELEASE SOFTWARE (fc3)? Background: we have a WAN where ...
4
votes
2answers
283 views

Cisco QoS algorithm - classification process

Question about the classification process of the Cisco QoS. I understand the concept, but I have some misunderstanding regarding the Cisco QoS algorithm. Am I true with the following reasoning: The ...
4
votes
1answer
930 views

QoS between two sites

I have a following topology where Internet service providers for both sites provide 10Mbps connection: There is a GRE tunnel between the sites and I would like to ensure that this tunnel is up even ...
4
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2answers
727 views

QoS for 100mb Circuit

The carrier has given me a COS profile of 102: 80/10/10 80% RT for a new 100mb circuit. I've compiled the below as my QoS policy-map and bandwidth configs. interface GigabitEthernet0/0 speed 100 ...
4
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2answers
2k views

How does a router/switch know which queue a packet should be put in?

In weighted fair queuing, how does the router/switch/multiplexer know which queue to put a packet into? For example does it read the headers of each packet to find out the sender and the intended ...
4
votes
1answer
75 views

Network Control Packets and QoS

In RFC 4594, titled as "Configuration Guidelines for DiffServ Service Classes", it is suggested that network control packets should be tagged by DSCP 48 (CS6). Protocols like OSPF, EIGRP, ISIS and so ...
4
votes
1answer
569 views

Why doesn't ISPs reset DSCP at the edge before delivering traffic to customers?

Some ISPs are doing QoS based on traffic type (online streaming), such as Comcast and Cogent. Why don't they reset IP DSCP at the edge so it is not as obvious that they are doing some kind of traffic ...
4
votes
1answer
443 views

QoS Policing vs Shaping, why policing

Regarding QoS, we have two modes: shaping or policing. The policing drops packets while shaping put the packets in buffer. Shaping seems to be the better solution in a general ways, so, why use ...
4
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2answers
389 views

Trust dscp command missing on cisco 3850

We have an incoming QoS configuration on our 2960X switches like this: class-map match-any QOS_GL_TRUST match ip dscp 8 16 24 32 46 class-map match-any QOS_GL_CITRIX match access-group name ...
4
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1answer
107 views

QoS on 2960X does not seem to have an impact

We have some issues with Dect stations that have a very high requirement in regards of delay. Communication between 2 devices should not exceed 500 microseconds (0.5ms). We decided to test some ...
4
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3answers
5k views

QoS or more bandwidth?

Being in SP field I sometimes hear folks say "we do not need QoS, just let's make sure we have enough bandwidth". This has always been bothering me, because currently we have a network without any QoS ...
4
votes
1answer
2k views

QoS, Marking map not marking properly

I have small problem with my edge router. I use QoS, standard CBWFQ template with one LLQ queue. Howewer I have match in access-list of 'ef' class, router probably not mark packet properly. My ...
4
votes
1answer
1k views

How do you control WAN Download Bandwith on an ASA?

I have a Cisco ASA and cannot seem to control bandwith from the Internet to the device that well. The ASA supports Shaping, but only on outbound traffic which works great. My question is how to ...
4
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1answer
7k views

Understand the output of “sh policy-map int” in Cisco IOS

I have a following CBWFQ configuration: ! ip access-list extended GRE-traffic-ACL permit ip host 10.10.11.2 host 10.10.11.1 ! ! class-map match-all GRE-traffic match access-group name GRE-traffic-...
4
votes
2answers
430 views

How to override 802.1p CoS on outgoing interfaces?

In Cisco, this can be easily achieved by: policy-map TVPrio description Set VLAN priority to 4 class class-default set cos 4 and apply this policy-map to the interface. How to do equivalent in ...
4
votes
2answers
213 views

Aggressive UDP flows

I am reading about the DBL feature on the Cisco 4500E which protect the buffers from filling up with traffic that is identified as nonadaptive or belligerent flows such as aggressive UDP flows. Since ...
4
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2answers
889 views

Equal WAN bandwidth for all LAN devices using Sonicwall NSA 2400/2600

I have a Sonicwall NSA 2400 (soon to replace with NSA 2600). The LAN has a widely varying number of users/devices. Some days there are 10 people onsite, some days 75-100. I want to be able to ...
4
votes
1answer
299 views

protect sensitive traffic if end-to-end QoS is not possible

I have a very typical scenario where I would like to protect IP phones traffic from high RTT, packet delay variation and packet loss on congested links. I fully understand, that QoS would help only in ...
3
votes
3answers
834 views

LAN QoS for VoIP

Is LAN QoS required for VoIP applications? We have basic network infrastructure: PC (Softphone) -GigEth-> [Switch] -GigEth-> [Router/Firewall] -> Internet (100 Mbps) -> [ITSP] Voice ...
3
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1answer
1k views

QoS on tunnel interface

My configuration policy-map Shape_FTP class FTP shape average percent 5 class class-default fair-queue policy-map Shaper class class-default shape average percent 100 service-policy ...
3
votes
1answer
169 views

STP packets and QoS

Routing protocol packets are IP packets and therfore they could have different DSCP values to have different priorities (which is implemented by QoS policy) during congestion. How about non-IP packets?...
3
votes
2answers
415 views

QoS for OSPF, VOICE and CRITICAL Traffic

I plan to implement the QoS policy below. The target is to garantee bandwidth to VOICE and CRITICAL traffic. It should be 1/3 for Voice and Video, 1/3 for Business Critical traffic, 1/3 for all the ...
3
votes
2answers
219 views

Applying a queuing service policy

This is on a Nexus N5624Q. I have this TA-queuing service policy : policy-map type queuing TA-queuing class type queuing queue-cos1 bandwidth percent 20 class type queuing queue-cos2 ...
3
votes
1answer
29 views

Access and uplinks ports QoS Queuing model

On an access switch, does the uplinks egress QoS Queuing model (multiple traffic classes and bandwidth reservation), should be different than the access ports egress Queuing model ? Is there a sense ...
3
votes
2answers
222 views

Hierarchical QoS

As I understood, the main difference between H-QoS and QoS is the level of category granularity, in which we could apply different QoS tools and policies. For example in simple QoS, just ...
3
votes
1answer
466 views

Cisco QoS SRR Share & Shape impact

I am working on understanding the impact of using shaping and sharing with the SRR scheduler. Given these 2 commands on an interface: switch(config-if)#srr-queue bandwidth share 40 20 30 20 switch(...
3
votes
2answers
380 views

QoS: priority-queue out

I'm trying to understand the priority-queue out command configured on an interface. Based on what I have read, here is what it does : the Priority Queue (Queue 1) on the switch will be emptied before ...
3
votes
1answer
101 views

Is Cisco SG300-10PP & QoS appropriate to share bandwidth?

We're going to let some empty space in our office building soon. The potential client needs an internet connection for their systems (including VoIP).For ourselves we have a resilient ethernet setup, ...
3
votes
1answer
546 views

Cisco MLS and MQC QoS - trust cos/dscp

A question about Cisco MLS and MQC QoS. I read two things on a Cisco guide: https://www.cisco.com/c/en/us/support/docs/switches/catalyst-3850-series-switches/118629-technote-qos-00.html On the ...
3
votes
1answer
895 views

QoS - Difference between MQC and HQF

I understand that the older versions of Cisco IOS implemented the MCQ and the newer one's implement HQF. Could some explain what is the difference between MQC and HQF? Thank you.
3
votes
1answer
209 views

Throttle traffic over a link?

I work for a global company in the client support department. Another department manages the network. My team is frequently asked to throttle client traffic from our on-premises Apple software update ...
3
votes
2answers
5k views

Limit bandwidth in cisco router with policy-map doesn't work

I have a problem with my scenario in limiting bandwidth of ubuntu PC in GNS3 with class-map and policy-map. this is my topology in GNS3: The R1 is a cisco 3725 router with c3725-adventerprisek9-mz....
3
votes
1answer
2k views

Configuring VLAN-based priority/QOS on Brocade NOS?

I would like to do QoS based on port-based VLAN traffic on a Brocade VDX67xx series router running NOS 4.1. Just need a way to say, "traffic on VLAN 100 has a higher priority ingress/egress than vlan ...
3
votes
1answer
3k views

How to test Wi-Fi Multimedia (WMM) QoS management with LANforge?

I would like to test the Wi-Fi Multimedia (WMM) feature of an access point AP. How can I test it using Candela Technologies LANforge-WiFIRE WiFi traffic generator? Some thoughts after reading the ...
3
votes
2answers
915 views

Extract QoS Buffer Drops via SNMP

I am in the process of rolling out solarwinds for visibility of QoS performance using netflow and CBQOS to show QoS class usage. One thing I am unsure of is what type of monitoring is available on L2 ...
3
votes
1answer
1k views

Rate limiting specific IP adresses on Cisco 2960S and 2960X series

We are looking into rate limiting some specific IP addresses down to 5mbit for various bandwidth reasons. Is is possible to rate limit ingress and egress traffic for specific IP addressees on the ...
2
votes
1answer
206 views

Qos Packet drops

My question is : This subinterface has a Qos policy settings its speed to 800000 (800kbps) If i have an offered rate of only 19000 bps, why is there a drop rate of drop rate 3000 bps ? Service-...
2
votes
2answers
63 views

How did the sender detect the reciver speed?

Let us say we have switch with multiple gigabit interfaces and there is two machines connected to that switch, one with gigabit NIC and one with 100 mbps NIC and we start copying file from the gigabit ...
2
votes
2answers
374 views

Cisco QoS Confirmation

Can anyone doublecheck my basic Cisco QoS configuration. I've got a small remote site connected via AT&T 20Mb line that communicates over an IPSec tunnel. class-map match-any QoS-Voice match ip ...
2
votes
1answer
5k views

QoS bandwith calculation

Please explain: I have two routers with QoS on them.. Both WAN-facing interfaces have a bandwidth command with the same value (100000) but the priority queue (also the other reservations) calculates ...
2
votes
1answer
2k views

Default QoS Behavior on Catalyst 3650/3850 Running IOS XE 16.3.6

I am trying to better understand the default queuing behavior on Catalyst 3650/3860 running IOS XE 16.3.6 Denali. Is QoS enabled globally by default? Coming from working with Catalyst 2960X on IOS 15 ...
2
votes
3answers
178 views

What transmission service gurantees does Ethernet give?

Higher layer transmission protocols have certain properties. For example, TCP "guarantees" duplicate-free, error-free in-order delivery of packets. UDP does basically provide the same properties as IP,...
2
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2answers
2k views

How does throttling of network traffic work for TCP/IP?

I have tried to find the answer on how network throttling works e.g. by ISP when they limit your access to say 100 Mbps. As far as I know TCP/IP itself does not have any mechanisms for that, so it is ...
2
votes
1answer
176 views

Cisco nexus 9396PX TX output discard on 40G interface without link congestion

We have cisco nexus 9396PX with N9K-M12PQ module (12x40G Interface), We have 8x10G L3 LACP bonded connectivity with our ISP and so far so good no issue at all. but recently we migrated that LACP LAg ...
2
votes
1answer
194 views

Do unmanaged switches honour QoS priorities set by managed switches?

Details about the devices We have a 24 port NETGEAR managed POE switch that has QoS capabilities. We also have the following unmanaged switches, 24 port Cisco POE, 48 port Cisco, 48 port NETGEAR, ...
2
votes
1answer
930 views

Quality of Service: Questions about input and output service policies prioritizing the same traffic

This question/lab was created with Cisco networking hardware. I have asked this question else where with no responses. I am new to QoS, but I have spent the last few days researching and I've ...
2
votes
2answers
381 views

Match DSCP in IPv4/IPv6 packets is not supported for this interface

i have cisco asr 903 (ios xe) i need to limitation Traffic for google-traffic this my configuration ip access-list extended ip-google-traffic permit ip 8.8.4.0 0.0.0.255 any permit ip 8.8.8.0 0.0....
2
votes
1answer
665 views

MLS QoS to MQC conversion

Currently trying to convert MLS QoS to MQC QoS, I'm facing a problem. In MLS (3750), and auto QoS we have this configuration for INPUT QUEUES: mls qos srr-queue input bandwidth 90 10 So in input 90% ...