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Topic: DiffServ

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In the News (Tue 23 Jul 19)

  Differentiated services - Wikipedia, the free encyclopedia
DiffServ or Differentiated Services is a computer networking architecture that specifies a simple, scalable and coarse-grained mechanism for classifying, managing network traffic and providing quality of service (QoS) guarantees on modern IP networks.
DiffServ can, for example, be used to provide low-latency, guaranteed service (GS) to critical network traffic such as voice or video while providing simple best-effort traffic guarantees to non-critical services such as web traffic or file transfers.
DiffServ operates on the principle of traffic classification, where each data packet is placed into a limited number of traffic classes, rather than differentiating network traffic based on the requirements of an individual flow.
en.wikipedia.org /wiki/Differentiated_Services   (2141 words)

 Differentiated services - Wikipedia, the free encyclopedia
The DiffServ model does not make judgement on what types of traffic should be given priority treatment since that is left up to the network operator.
One advantage of DiffServ, is that all the policing and classifying is done at the boundaries between DiffServ clouds.
Since DiffServ is simply a mechanism for deciding which packets to delay or drop at the expense of others in a situation where there is not enough network capacity, consider that when DiffServ is working by dropping packets selectively, traffic on the link in question must already be very close to saturation.
en.wikipedia.org /wiki/Differentiated_services   (2141 words)

 Yee's Homepage | QoS | DiffServ
DiffServ] provides a simple and coarse method of classifying services of various applications.
DiffServ assumes the existence of a service level agreement (SLA) between networks that share a border.
When DiffServ uses RSVP parameters or specific application types to identify and classify constant-bit-rate (CBR) traffic, it will be possible to establish well-defined aggregate flows that may be directed to fixed bandwidth pipes.
www.hep.ucl.ac.uk /~ytl/qos/diffserv_01.html   (592 words)

 RFC 2998 - A Framework for Integrated Services Operation over Diffserv Networks
RFC 2998 Integrated Services Over Diffserv Networks November 2000 Note that, for the purposes of this document, the defining features of a Diffserv region is the type of classification and traffic control that is used for the delivery of end-to-end QOS for a particular application.
Diffserv network regions must be able to pass RSVP messages, in such a manner that they can be recovered at the egress of the Diffserv network region.
The larger Diffserv network regions are thus focused on the task of protecting their networks, while the Intserv-capable nodes are focused on the task of shaping and policing their own traffic to be in compliance with their negotiated Intserv parameters.
www.muonics.com /rfc/rfc2998.php   (9359 words)

 Diffserv Vs. MPLS
Diffserv (differentiated services) and MPLS (Multiprotocol Label Switching) are two separate standards which purport to help solve the IP quality problem.
Diffserv takes the IP TOS (type of service) field, renames it the DS byte, and uses it to carry information about IP packet service requirements.
Diffserv relies on traffic conditioners sitting at the edge of the network to indicate each packet's requirements.
www.protocols.com /papers/diffserv.htm   (206 words)

 DiffServ -- The Scalable End-to-End QoS Model  [QoS Signaling] - Cisco Systems
DiffServ, on the other hand, addresses the clear need for relatively simple and coarse methods of categorizing traffic into different classes, also called Class of Service (CoS), and applies QoS parameters to those classes.
In DiffServ, signaling for QoS is eliminated, and the number of states required to be kept at each network element is drastically reduced, resulting in a coarse-grained, scalable end-to-end QoS solution.
The MQC forms the basis for provisioning DiffServ, and all the QoS mechanisms are part of the class-maps (classification), or policy-maps (policing, shaping, queuing, congestion avoidance, packet marking, Layer2 CoS marking, etc.).
www.cisco.com /en/US/tech/tk543/tk766/technologies_white_paper09186a00800a3e2f.shtml   (5121 words)

 Cisco¬†- DiffServ Frequently Asked Questions   (Site not responding. Last check: 2007-09-17)
Diffserv is a new model by which traffic is treated by intermediate systems with relative priorities based on the type of services (ToS) or Dynamic Host Configuration Protocol (DHCP) field.
The Diffserv standard proposes to increase the number of definable priority levels by re-allocating bits of an IP packet for priority marking.
The Diffserv proposal is meant to allow a finer granularity of priority setting for the applications and devices that can make use of it, but it does not specify interpretation (that is, action to be taken).
www.univ.kiev.ua /~roman/QoS/dffs_qa.htm   (1181 words)

 The ns MPLS/diffserv patch
Since diffserv and MPLS are quite complementary technologies designed to address different problems, the diffserv and MPLS patches had very little overlap and the integration was really quite easy.
Diffserv operates at the network layer and MPLS operates at the link layer (although it is often said operate somewhere between the link layer and the network layer due to its path-based nature).
Hence, the diffserv codepoint, which is stored in the IP header, is not visible when switching MPLS packets.
www.eeng.dcu.ie /~murphys/ns-work/mpls-diffserv/index.html   (689 words)

 DiffServ - voip-info.org
DiffServ is a QoS (Quality of Service) protocol for managing bandwidth allocation for Internet media connections (e.g.
Asterisk 1.0.9 (ie sip.conf) - EF DiffServ hexadecimal: tos = 0xb8
> Asterisk 1.0.9 (ie sip.conf) - EF DiffServ hexadecimal: tos = 0xb8
www.voip-info.org /wiki/view/DiffServ   (585 words)

 Roxen Community: RFC 3290 An Informal Management Model for Diffserv Routers (Informational)   (Site not responding. Last check: 2007-09-17)
Diffserv routers may reject or admit RSVP reservation requests to provide a means of admission control to Diffserv-based services or they may use these requests to trigger provisioning changes for a flow-aggregation in the Diffserv network.
Diffserv nodes may apply shaping, policing and/or marking to traffic streams that exceed the bounds of their TCS in order to prevent one traffic stream from seizing more than its share of resources from a Diffserv network.
When the Diffserv treatment for a given packet needs to have such building blocks repeated, this is performed by cascading multiple TCBs: an output of one TCB may drive the input of a succeeding one.
community.roxen.com /developers/idocs/rfc/rfc3290.html   (13786 words)

 Roxen Community: RFC 2998 A Framework for Integrated Services Operation over Diffserv Networks (Informational)   (Site not responding. Last check: 2007-09-17)
Note that, for the purposes of this document, the defining features of a Diffserv region is the type of classification and traffic control that is used for the delivery of end-to-end QOS for a particular application.
By including routers interior to the Diffserv network region in RSVP signaling, it is possible to simultaneously improve the efficiency of resource usage within the Diffserv region and to improve the level of confidence that the resources requested at admission control are indeed available at this particular point in time.
In this approach, described in [3], routers in the Diffserv network region respond to the standard per-flow RSVP signaling originating from the Intserv-capable nodes outside the Diffserv region.
community.roxen.com /developers/idocs/rfc/rfc2998.html   (8939 words)

 DiffServ: Differentiated Service Architecture in IP Network (RFC 2474 2475)
DiffServ architecture is composed of a number of functional elements implemented in network nodes, including a small set of per-hop forwarding behaviors, packet classification functions, and traffic conditioning functions including metering, marking, shaping, and policing.
Protocol Structure - DiffServ: Differentiated Service ArchitectureIn DiffServ, a replacement header field, called the DS field, is defined, which is intended to supersede the existing definitions of the IPv4 TOS octet and the IPv6 Traffic Class octet.
DiffServ architecture is defined by IETF (http://www.ietf.org) RFC 2474 and 2475.
www.javvin.com /protocolDiffServ.html   (371 words)

 [No title]
Introduction As the Diffserv work has evolved, there have been several cases where terminology has needed to be created or the definitions in Diffserv standards track RFCs have needed to be refined.
In particular, the "Currently Unused" (CU) bits of the DS Field have not been assigned to Diffserv, and subsequent to the publication of RFC 2474, they were assigned for explicit congestion notification, as defined in RFC 3168 [4].
The consensus of the DiffServ working group is that BCP 37 correctly restates the structure of the former TOS and traffic class fields.
www.ietf.org /rfc/rfc3260.txt?number=3260   (2747 words)

 Linux and the Next Generation Internet | Linux Journal
The term ``Diffserv'' refers to an approach for implementing such capabilities which is being defined (through the usual method of constructing Internet standards) to be broadly compatible with the scope and flavor of the global Internet (see Resources 1).
As a result of the stated goals and the architecture of Diffserv, the only way to minimize these effects is to practice ``gross overprovisioning'', where only a small percentage of the available bandwidth is made available to the EF class, and only a few EF streams are allowed.
Once the packets have been tagged and admitted into the interior of the Diffserv domain, ``core'' routers simply have to examine each packet's DSCP and assign it to the corresponding output queue to be forwarded on to the next node.
www.linuxjournal.com /article.php?sid=3928   (3610 words)

 Some notes on the use of my ns diffserv software
This is consistent with the notions in the diffserv documentation.
In previous versions of my patch, the source and destination matching algorithms were very simple: the source parameter could match everything or one source, the destinations were the same, but were more flexible, since a number of destinations could be present in the profile.
When I wanted to implement a new type of access to a link namely a scheduler that has diffserv capabilities I thought that the easiest way to do it was to write a new OTcl method to install a link with a scheduler associated with it.
www.eeng.dcu.ie /~murphys/ns-work/diffserv/notes.html   (3286 words)

This class (DiffServPacketClassifier) is used to define the DiffServ packet flows coming into a router with DiffServ packet processing capability.
For the measurement of the arrival rate of the DiffServ class-type packets, Token Bucket Meter (TBM) is used with SRTCM (Single Rate Three Color Marker) or TRTCM (Two Rate Three Color Markter).
In weighted scheduling, weight for each queue is allocated, and the relative portion of the bandwidth is allocated to the queue according to its weight.
snad.ncsl.nist.gov /glass/doc/api_1.0/gov/nist/antd/diffserv/package-summary.html   (366 words)

 Differentiated Services on Linux
Differentiated Services (short: Diffserv) is an architecture for providing different types or levels of service for network traffic.
One key characteristic of Diffserv is that flows are aggregated in the network, so that core routers only need to distinguish a comparably small number of aggregated flows, even if those flows contain thousands or millions of individual flows.
The Diffserv code for 2.2 kernels is no longer maintained.
diffserv.sourceforge.net   (482 words)

 Implementing DiffServ for End-to-End Quality of Service
With the ability of the system to mark packets according to DSCP setting, collections of packets with the same DSCP setting and sent in a particular direction can be grouped into a BA.
To preserve backward-compatibility with any IP Precedence scheme currently in use on the network, DiffServ has defined a DSCP value in the form xxx000, where x is either 0 or 1.
Figure 1 shows a sample DiffServ implementation with three routers: Remote router 1, central router, and remote router 2.
www.cisco.com /univercd/cc/td/doc/product/software/ios121/121newft/121t/121t5/dtdfsv.htm   (2529 words)

 RTCL - Differentiated Services   (Site not responding. Last check: 2007-09-17)
While this was a satisfactory service type for a long time of the Internet life, nowadays many new applications are working on the Internet with new service requirements and more strict characteristics and these applications used to employ variant and sometimes nonstandard techniques to provide the amount of guarantees required for acceptable performance.
Briefly, DiffServ is built upon a simple model of traffic conditioning and policing at the edges of the network in addition to classification to different service classes, then the traffic is forwarded using simple differentiated treatments (called per-hop behaviors or PHBs) in the core of the network.
Currently the DiffServ framework is in the stage of standardization and experimentation, and many new solutions for the basic problems are still being evaluated and tested.
kabru.eecs.umich.edu /qos_network/diffserv/DiffServ.html   (595 words)

 Quality of Service - Differentiated Services - Diffserv
Diffserv is a simple method of providing differentiated classes of service, also known as Quality of Service, for Internet traffic.
A small bit-pattern in each IP packet is used to mark a packet to receive a particular forwarding treatment, or per-hop behavior (PHB), at each network node.
Since the receiving rate of EF traffic is always smaller than the sending rate at every router, the EF traffic is guaranteed for minimized delay and assured bandwidth.
www.interpeak.com /focus/diffserv.html   (478 words)

 Ashley Laurent: Products   (Site not responding. Last check: 2007-09-17)
DiffServ, short for Differentiated Services, is a quality of service (QoS) method for classifying and prioritizing IP traffic.
At the beginning of the flow, all traffic is classified and then, it is forwarded based on rules defined at the router.
An example of DiffServ in use would be a converged network that handles both data and voice.
www.ashleylaurent.com /products/bw2-0/diffserv.htm   (203 words)

 Check Point Software: FloodGate-1 - DiffServ Support
DiffServ support enables service providers with IP networks to offer end-to-end Quality of Service (QoS) for both VPN and unencrypted traffic.
DiffServ is supported in both standard IP networks and Multiprotocol Label Switching (MPLS) IP networks.
By integrating DiffServ and VPN functionality on the same device, FloodGate-1 solves the problem described above for a standalone QoS device.
www.checkpoint.com /products/floodgate-1/floodgate-1_diffserv.html   (389 words)

 DiffServ (differentiated services)
The DiffServ model for QoS was developed to differentiate IP traffic so that the traffic's relative priority could be determined on a per-hop basis.
DiffServ replaces the first bits in the ToS byte with a differentiated services code point (DSCP).
DiffServ, as described in RFC 2475, allows for five categories of service differentiation.
www.networkworld.com /details/660.html?def   (606 words)

 Re: Diffserv and NetApplications
On Fri, Jul 13, 2001 at 09:52:41PM +0530, SVR Anand wrote: Considering diffserv as QoS supporting mechanism, I am contemplating on the possibility of making some of the known netapplications like http, telnet, ftp and so on, inherently diffserv aware.
By this I mean the applications automatically send out their packets out of the box with appropriate dscp values depending on their QoS requirements.
While tc is one way of achieving the same result, it is an external mechanism requiring a seperate agent to configure diffserv.
oss.sgi.com /archives/netdev/2001-07/msg00026.html   (129 words)

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