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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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Designing a web-facing network for redundancy and QoS (in a small business)

Summary How does one configure the web-facing part of a small business network for redundancy and quality of service? I mean ... we can have the control over our internal infrastructure, but what ...
iDontKnow's user avatar
1 vote
1 answer
77 views

A question about WRED in QoS

I understand what WRED is and what goals it aims to achieve during congestion (drop packets, avoid Taildrop and so on). However, the actual principle of it is quite confusing to me. Consider this ...
Mitrixsen's user avatar
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1 answer
102 views

Correct interpretation "show mls qos"

I ask you to tell me in the correct interpretation of the output of commands on the Cisco Catalyst 3750. command "show mls qos interface fastEthernet 0/3 statistics". Outputs the following: ...
Глеб Щеголев's user avatar
1 vote
2 answers
79 views

How did ATM switches that were implemented in a core of IP network improve QoS and higher data rate?

How can ATM switch improve Quality of service and data rate just by incorporating them into the core of IP network? What was used in the sore of IP networks before ATM switches and what is used today ...
Vladimir Pejanovic's user avatar
0 votes
3 answers
133 views

How does policing prevent LLQ queue starvation? (QoS)

A networking course that I follow mentions the following information about LLQ (Low Latency Queuing) in QoS LLQ designates one (or more) queues as strict priority queues. This means that if there is ...
Mitrixsen's user avatar
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3 votes
1 answer
586 views

Are all 64 DSCP values usable/configurable?

I have read that DSCP consists of 6 bits, thus providing us with 64 DSCP marking values (0-63). If I understood all correctly, 21 of these values have been standardized and named (AF, EF, DF, etc) ...
Mitrixsen's user avatar
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1 vote
1 answer
49 views

How do multiple queues work ? (QoS)

A course I am watching mentions that an essential part of QoS is the use of multiple queues. How exactly do these multiple queues work? Are they built into the device or is manual configuration ...
Mitrixsen's user avatar
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1 vote
1 answer
674 views

Classification and Marking using PCP

A networking course that I am following mentions that layer 2 marking can be performed through the use of PCP in the dot1q tag. So to help me understand, once a switch receives a frame with a dot1q ...
Mitrixsen's user avatar
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1 vote
2 answers
441 views

Queuing and TCP Global Synchronization

About TCP global synchronization. If we have several hosts having TCP connections with some other hosts (over the internet, for example) and our network is congested, if there was a burst of traffic, ...
Mitrixsen's user avatar
  • 803
1 vote
1 answer
77 views

Why does congestion happen

Imagine a network full of routers . The job of a router is to be able to receive multiple packets from multiple sources then send the packets 1 at a time in each of its outputs.If the routers are able ...
Miss Mulan's user avatar
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2 answers
134 views

Where is priority for a particular frame set?

The Medium Access Control sublayer appends 3 bits for the priority of the frame. The possible choices for the priority are Traffic Type Priority Background 0 (lowest) Best effort 1 (default) ...
user84425's user avatar
1 vote
1 answer
231 views

Cisco ASR1006 QoS on pppoe session: Police percent not supported - no bandwidth for percent calculation

I want to perform QoS on specific (or all the) L2TP sessions that establish on ASR1006 router (LNS). What I have managed already is to set a police at a specific rate for a class that matches access-...
vlamb's user avatar
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2 votes
3 answers
69 views

QOS operation doubt

First of all, thanks for taking the time to read. I have a doubt. Does QOS marking in the IP header occur on every packet or does it need TCP segmentation established (TCP handshake)?
Joao's user avatar
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1 answer
42 views

QOS - CPU CoS Weight- pluribus switches

I have different switches and each switch has different cos-weight. Now, it has cos3-weight, cos4-weight and cos5-weight in one switch as 15. In other it is 30. As per this link : https://...
Tayto's user avatar
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0 answers
88 views

Matching QOS config from CAT 9300 to 2960XR

I am not familiar with the 2960XR syntax. I need help in matching my current QoS config that is currently on the Cisco 9300 to a cisco 2960XR. Thank you. The QoS config is of HQoS and follows: BRS-TC-...
vicko164's user avatar
1 vote
1 answer
884 views

Understand DSCP and Precedence Values in Ipv4 or Ipv6 packet

I read from this website to understand DSCP and it's corresponding IP precedence value. For example DSCP value is '000 000' which Drop Probability is N/A(never happen) and it's Equivalent IP ...
S. M.'s user avatar
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0 answers
78 views

5G: Mapping QoS flow to a DRB requiring out-of-order delivery

I understand that 5GNR allows out-of-order delivery for some DRBs by configuring them as such. Also, I understand that a QoS Flow is mapped by SDAP to a DRB based on QoS parameters provided from the ...
DDs's user avatar
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1 vote
1 answer
299 views

Are IPv4 type of service and IPv6 traffic class equivalent to each other or is traffic class IPv6 specific? [duplicate]

IPv6 has a traffic class field. According to the specification it is an IPv6 length, out of which first 6 bits are called code point or differential services code point (DSCP) and the last 2 bits are ...
S. M.'s user avatar
  • 398
1 vote
1 answer
2k views

Layer 2 (switch) QoS in a LAN or VLAN-based QoS

In my setup above (Cisco 2960 running IOS15), I have all devices marked in red in vlan 20 (WLAN_VLAN), devices in green in VLAN 10 (PC_VLAN) and devices in yellow which are VoIP in the voice vlan. I ...
user78234's user avatar
2 votes
2 answers
1k views

What's difference between traffic shaper and scheduler?

Can't find a clear answer in Google. Both drop packets when the queue is filled. So why two terms are used? If the shaper includes the scheduler, then what else do the shaper besides the dropping? Or ...
stckvrw's user avatar
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1 answer
139 views

Cisco IOS How to dynamically change the queueing/shaping upload bandwidth for xDSL circuits?

In Cisco 29xx routers with IOS 15.7, we have upload queues (with the classic service-policy output command and the policy-map: policy-map wan-shaping class class-default shape average 1024000 ...
Elias Bats's user avatar
1 vote
2 answers
518 views

how a transport-layer protocol can provide timing guarantees?

I'm reading a textbook which says: A transport-layer protocol can also provide timing guarantees. As with throughput guarantees, timing guarantees can come in many shapes and forms. An example ...
amjad's user avatar
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1 vote
1 answer
169 views

QoS Policy to not overutilize WAN link

I have a configuration on a Cisco C897VA-K9 router that has a built in DSL modem. It has a simple internet connection via VDSL. There is a VPN configured on the device, that connects back to our main ...
Mario Jost's user avatar
  • 1,709
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1 answer
161 views

How to compare two DSCP ? which one of DSCP 28 and 34 (decimal) has more priority?

How to compare two DSCP ? for example which one of DSCP 28 and 34 (decimal) has more priority ?
AMEL BENAIDA's user avatar
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1 answer
55 views

Traffic flow of tunnel interfaces

I would like to understand traffic flow in a router. In what direction do i need to apply a policy-map in order to affect traffic? Especially regading tunnel interfaces, as traffic both comes and goes ...
Mario Jost's user avatar
  • 1,709
3 votes
2 answers
297 views

Understanding traffic flow on SVIs [closed]

I have a simliar question to this one: Access-Lists and VLAN and understanding traffic flow But my question is concerning service-policies. Have a look at the image above. I triet to make a traffic ...
Mario Jost's user avatar
  • 1,709
1 vote
1 answer
1k views

How to verify the traffic forwarding class in Junos if it is set by firewall filter?

I have a firewall filter below which puts the ICMP traffic to assured-forwarding class if the bandwidth threshold is not exceeded: root@vmx> show configuration firewall filter example | display ...
Martin's user avatar
  • 1,063
0 votes
0 answers
109 views

Shaper configuration for Juniper MX480 - MPC3e 3D NG

following secario: A MX480 with MPC3e 3D NG Linecards. I have a new Layer2 Access provider that is providing Layer2 services between 100 and 1000MBit/s. My connection zu this services are a 10GE E-...
Andreas Schaefer's user avatar
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0 answers
34 views

can't find cbQosCMPostPolicyBitRate64 oid for cisco

i have use snmpwalk go get police Bit Rate Traffic policy-map(QOS) for my cisco ASR1006 but i need a 64bit barbecue my traffic is more of 5000Mbps so 32bit can't handle it . ~# snmpwalk -v2c -c aaa ...
Anas Programmer's user avatar
1 vote
0 answers
83 views

Upstream QoS garanteed bandwidth

In the network I'm trying to manage there is a satellite link, the upstream of which is ~ 7 Mbps. In this upstream, I need to allocate 1.5 Mbps of guaranteed bandwidth for one single host, but nothing ...
vudex's user avatar
  • 45
0 votes
0 answers
48 views

Rate limiting xFTP traffic originating from a Cisco IOS router

We have some routers on marginal cell links that we need to pull files from using TFTP or FTP. During file transfers connections to the router become so slow as to be unusable. Is there a way to rate-...
Stephen Craven's user avatar
0 votes
0 answers
56 views

uncorrected snmp Qos value from cisco

hello i have a router cisco 1006 and i create a policy-map with to class policy-map CheckBand-BandPerUsr class BandPerUsr police cir 10000000000 class class-default police cir 10000000000 ...
Anas Programmer's user avatar
1 vote
1 answer
86 views

QoS policy definition - Cisco guidelines vs reality

Currently designing a QoS Policy for a customer (Cat 4500 models), following the business needs, I will work on a 8-class based model definition. Cisco has several guidelines under this perspective, ...
bdes31's user avatar
  • 1,085
6 votes
3 answers
2k views

How to find the client who downloads a big file?

today I found out that somebody in our organization utilized our uplink for 100%. We have Cisco WLC 2500 where I could see in application monitoring that 80% traffic of the last 90 sec was a file ...
dtsn's user avatar
  • 93
2 votes
1 answer
1k views

Cisco 3850: Process responsible for Softbuffers

There is a command to increase the SoftMax Buffers on 3850 switches: qos queue-softmax-multiplier 200 This is done in percent which means i am doubling the amount of softmax buffer. Before, the ...
Mario Jost's user avatar
  • 1,709
0 votes
0 answers
667 views

QoS over IPSec Site-to-Site VPN: Concerns and Questions

(For clarification purposes: Kbps = Kilobits per second for bandwidth, KB/s = Kilobytes per second for file / data transfer stuff. I'm using them separately because XG knows KBps but not Kbps - ...
Thomas Ward's user avatar
3 votes
1 answer
319 views

What is the difference between Cisco's QoS models and strategies?

I have been reading about QoS and different strategies. From what I understand, Cisco proposes three different models and three different strategies for QoS. For strategies, you can have a 4-class, ...
ThomasFromUganda's user avatar
2 votes
2 answers
451 views

What is the advantage of Supervised Machine Learning over Deep Packet Inspection in Network Traffic Classification? [closed]

As per the definition of Deep Packet Inspection (DPI), it uses signatures for packet filtering. Supervised Machine Learning can help put a label on a packet which does not get identified by Deep ...
boomselector's user avatar
0 votes
3 answers
112 views

High Throughput on BGP Multihomed Network

I've One site connected to my server location via BGP over MPLS and at my server location 2 edge routers cater these WAN links, and are further connected to Servers via switches. Now, Is it possible ...
danish's user avatar
  • 141
0 votes
1 answer
674 views

What is the difference between meters and queues in Openflow?

I'm new to OpenFlow and have just started studying Software Defined Networking. I have found a multiple websites mentioning that queues and meters are complementary to each other, and that they should ...
boomselector's user avatar
1 vote
0 answers
89 views

HTTPS QOS and policing [closed]

In our office, everything runs on HTTPS. We have softphones and web-based clients which are high priority. We also have Google search, maps and other low priority websites that should work on best-...
user36337's user avatar
  • 113
0 votes
1 answer
2k views

Cisco qos, service-policy on output interface on 1100 ISR seems ignored

I am trying to configure QoS for a specialty purpose application, and it is the first time I have done QoS. This is on an 1100 ISR with IOS XE 16.09.03. The device is a set of 4 that establish a mesh ...
Linwood's user avatar
  • 227
1 vote
1 answer
288 views

Unable to see packet drops on tunnels

I have the following topology set on AWS where there are 4 CSR 1000v Routers deployed and Segment Routing enabled in which the Segment Routing Headend is R1 and the destination is R3. I aim to send ...
Khalil Mebarkia's user avatar
1 vote
1 answer
192 views

Packet scheduling in LTE/5G core network components

Scheduling algorithms must be used on the radio side of these technologies in order to map radio sources to incoming/outgoing data packets and satisfy quality of service requirements such as latency ...
tyb's user avatar
  • 13
0 votes
0 answers
230 views

I'm unable to see packet drops after configuration of QoS policy

I aim to send iperf traffic from Endpoint1(Client) to Endpoint2 (Server) with the following SR path = {R1, R2, R3, R4, R3, R2, R1, R2, and R3}. First of all, the traffic generated by iperf from ...
Khalil Mebarkia's user avatar
0 votes
0 answers
118 views

Cisco Catalyst QoS queuing model

How Cisco Hardware queuing model (like 1p7q4t for Cat6800) are related to traffic classes (class-map) ? How assign the X traffic class to Y hardware queue ? Also, if only 6 classes are configured, ...
bdes31's user avatar
  • 1,085
1 vote
1 answer
153 views

Suggestion for Weights for Weighted Round Robin

I have looked over the book "End-to-End QoS Network Design" by Tim Szigeti et al. and RFC4594. The RFC proposes 14 Service class: I have a switch with simple QoS features. It has 14 egress queues on ...
A.A's user avatar
  • 551
3 votes
1 answer
533 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?...
A.A's user avatar
  • 551
4 votes
1 answer
863 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 ...
A.A's user avatar
  • 551
2 votes
1 answer
1k 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 ...
Satish's user avatar
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