Onnowpurbo at 00:37, 21 November 2022

2022-11-21T00:37:32Z

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2022-11-21T00:23:37Z

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Sumber: https://www.techtarget.com/searchnetworking/definition/Class-of-Service-CoS#:~:text=Class%20of%20Service%20(CoS)%20is,level%20of%20network%20service%20priority.

Class of Service (CoS) is a way of managing traffic in a network by grouping similar types of traffic -- such as email, streaming video, voice over IP and large document file transfer -- together and treating each type as a class with its own level of network service priority.

CoS is used at the data link layer -- Layer 2 -- of the Open Systems Interconnection (OSI) model and consists of a 3-bit field within the 802.1Q virtual local area network (VLAN) or 802.1P frame header.

==How does CoS work?==

The three CoS bits can be used to specify a priority value of the frame. The values range between zero and seven, where zero is for the lowest priority traffic and seven is for the highest priority traffic. Once a frame is defined with a priority value, Layer 2 switches that have quality of service (QoS) enabled can use these priority numbers and prioritize the outbound delivery of frames on an interface when a link becomes congested and queuing is required. Network switches can be configured to trust the CoS values or ignore or overwrite them prior to sending them out the destination interface.

Frames that are tagged with higher-priority CoS values are sent out the interface first, while lower-level CoS values will wait in a queue to be sent. This is why CoS is important for real-time streaming data, such as voice and video. CoS helps to prioritize this traffic so it does not get held up in a queue or dropped by the interface, which can cause stuttering or network jitter on the voice or video stream. Alternatively, data flows such as File Transfer Protocol that do not require low-latency transport to operate can be given lower CoS values so that higher-priority traffic can be processed and sent out the interface first.

==How are CoS, DSCP and QoS related?==

QoS is a queue strategy mechanism on networks that is used to ensure that higher-priority traffic is given preferential treatment on network interfaces when high-link utilization results in a bottleneck. When bottlenecks occur, switching and routing interfaces use memory buffers known as queues to delay the sending of frames or packets until the bottleneck is cleared. QoS consists of the following three processes:
* traffic marking or classification;
* matching of queuing policy based on pre-configured classes; and
* enforcing queuing policy to network interfaces.

The first step -- marking or classifying traffic -- is where both CoS and Differentiated Services Code Point (DSCP) techniques reside within QoS. As mentioned previously, CoS operates at Layer 2 of the OSI model and consists of eight different classification groups to which Ethernet frames can belong. DSCP serves a similar purpose as CoS, but it does so at the network layer -- Layer 3 -- of the OSI model and uses a 6-bit field, as opposed to only 3 bits.

The other two steps in the QoS process are automated by the router or switch as it works to place packets into queuing groups and enforces the transmission, queuing or dropping of frames and packets based on configured classification markings.

[[File:Osi model-f.png|center|300px|thumb|The OSI model showing the data link layer, CoS value, network layer and DSCP value]]

With DSCP, the priority values are contained inside the IP header, as opposed to the Ethernet frame with CoS. Additionally, DSCP can be broken into 64 distinct groups -- values zero to 63. That means that DSCP can be used on Layer 3 routed interfaces, and traffic can be separated into more queue groups, providing greater granularity when it comes to traffic prioritization.

==Referensi==

* https://www.techtarget.com/searchnetworking/definition/Class-of-Service-CoS#:~:text=Class%20of%20Service%20(CoS)%20is,level%20of%20network%20service%20priority.

@@ Line 2: / Line 2: @@
-Class of Service (CoS) is a way of managing traffic in a network by grouping similar types of traffic -- such as email, streaming video, voice over IP and large document file transfer -- together and treating each type as a class with its own level of network service priority.
+Class of Service (CoS) adalah cara mengelola lalu lintas dalam jaringan dengan mengelompokkan jenis lalu lintas yang serupa -- seperti email, streaming video, voice over IP, dan transfer file dokumen besar -- bersama-sama dan memperlakukan setiap jenis sebagai kelas dengan tingkat prioritas layanan jaringan sendiri.
-CoS is used at the data link layer -- Layer 2 -- of the Open Systems Interconnection (OSI) model and consists of a 3-bit field within the 802.1Q virtual local area network (VLAN) or 802.1P frame header.
+CoS digunakan pada lapisan data link -- Lapisan 2 -- dari model Open Systems Interconnection (OSI) dan terdiri dari 3-bit field dalam virtual local area network (VLAN) 802.1Q atau  frame header 802.1P.
-==How does CoS work?==
+Tiga bit CoS dapat digunakan untuk menentukan nilai prioritas dari frame. Nilainya berkisar antara nol dan tujuh, di mana nol untuk lalu lintas dengan prioritas terendah dan tujuh untuk lalu lintas dengan prioritas tertinggi. Setelah frame ditentukan dengan nilai prioritas, Switch Lapisan 2 yang mengaktifkan quality of service  (QoS) dapat menggunakan nomor prioritas ini dan memprioritaskan pengiriman outbound frame pada interface ketika link menjadi padat dan diperlukan antrean. Switch jaringan dapat dikonfigurasi untuk memercayai nilai CoS atau mengabaikan atau menimpanya sebelum mengirimkannya ke interface tujuan.
-The three CoS bits can be used to specify a priority value of the frame. The values range between zero and seven, where zero is for the lowest priority traffic and seven is for the highest priority traffic. Once a frame is defined with a priority value, Layer 2 switches that have quality of service (QoS) enabled can use these priority numbers and prioritize the outbound delivery of frames on an interface when a link becomes congested and queuing is required. Network switches can be configured to trust the CoS values or ignore or overwrite them prior to sending them out the destination interface.
+Frame yang diberi tag dengan nilai CoS dengan prioritas lebih tinggi dikirim keluar interface terlebih dahulu, sedangkan nilai CoS dengan level lebih rendah akan menunggu dalam antrian untuk dikirim. Inilah mengapa CoS penting untuk data streaming real-time, seperti suara dan video. CoS membantu memprioritaskan lalu lintas ini sehingga tidak tertahan dalam antrean atau dibuang oleh interface, yang dapat menyebabkan kegagapan atau gangguan jaringan pada aliran suara atau video. Alternatifnya, aliran data seperti File Transfer Protocol yang tidak memerlukan transportasi latensi rendah untuk beroperasi dapat diberikan nilai CoS yang lebih rendah sehingga lalu lintas dengan prioritas lebih tinggi dapat diproses dan dikirim keluar interface terlebih dahulu.
-Frames that are tagged with higher-priority CoS values are sent out the interface first, while lower-level CoS values will wait in a queue to be sent. This is why CoS is important for real-time streaming data, such as voice and video. CoS helps to prioritize this traffic so it does not get held up in a queue or dropped by the interface, which can cause stuttering or network jitter on the voice or video stream. Alternatively, data flows such as File Transfer Protocol that do not require low-latency transport to operate can be given lower CoS values so that higher-priority traffic can be processed and sent out the interface first.
+==Bagaimana CoS, DSCP dan QoS terkait?==
-==How are CoS, DSCP and QoS related?==
+QoS adalah mekanisme strategi antrian pada jaringan yang digunakan untuk memastikan bahwa lalu lintas dengan prioritas lebih tinggi diberikan perlakuan istimewa pada interface jaringan ketika pemanfaatan link tinggi menghasilkan bottleneck. Ketika bottleneck terjadi, interface switching dan routing menggunakan buffer memori yang dikenal sebagai antrian untuk menunda pengiriman frame atau paket sampai bottleneck dibersihkan. QoS terdiri dari tiga proses berikut:
-QoS is a queue strategy mechanism on networks that is used to ensure that higher-priority traffic is given preferential treatment on network interfaces when high-link utilization results in a bottleneck. When bottlenecks occur, switching and routing interfaces use memory buffers known as queues to delay the sending of frames or packets until the bottleneck is cleared. QoS consists of the following three processes:
+* traffic marking atau classification;
-* traffic marking or classification;
+* matching dari queuing policy berbasis pada  pre-configured class; dan
-* matching of queuing policy based on pre-configured classes; and
+* enforcing queuing policy ke network interface.
-The first step -- marking or classifying traffic -- is where both CoS and Differentiated Services Code Point (DSCP) techniques reside within QoS. As mentioned previously, CoS operates at Layer 2 of the OSI model and consists of eight different classification groups to which Ethernet frames can belong. DSCP serves a similar purpose as CoS, but it does so at the network layer -- Layer 3 -- of the OSI model and uses a 6-bit field, as opposed to only 3 bits.
+Langkah pertama -- marking atau mengklasifikasikan lalu lintas -- adalah saat teknik CoS dan Differentiated Services Code Point (DSCP) berada di dalam QoS. Seperti disebutkan sebelumnya, CoS beroperasi pada Layer 2 dari model OSI dan terdiri dari delapan kelompok klasifikasi berbeda yang dapat menjadi anggota frame Ethernet. DSCP melayani tujuan yang sama seperti CoS, tetapi melakukannya pada lapisan jaringan -- Lapisan 3 -- model OSI dan menggunakan field 6-bit, bukan 3 bit.
-The other two steps in the QoS process are automated by the router or switch as it works to place packets into queuing groups and enforces the transmission, queuing or dropping of frames and packets based on configured classification markings.
+Dua langkah lain dalam proses QoS diotomatisasi oleh router atau switch karena berfungsi untuk menempatkan paket ke dalam kelompok antrian dan memberlakukan transmisi, antrian atau menjatuhkan frame dan paket berdasarkan penandaan klasifikasi yang dikonfigurasi.
 [[File:Osi model-f.png|center|300px|thumb|The OSI model showing the data link layer, CoS value, network layer and DSCP value]]
-With DSCP, the priority values are contained inside the IP header, as opposed to the Ethernet frame with CoS. Additionally, DSCP can be broken into 64 distinct groups -- values zero to 63. That means that DSCP can be used on Layer 3 routed interfaces, and traffic can be separated into more queue groups, providing greater granularity when it comes to traffic prioritization.
+Dengan DSCP, nilai prioritas terdapat di dalam header IP, berbeda dengan frame Ethernet dengan CoS. Selain itu, DSCP dapat dipecah menjadi 64 grup berbeda -- bernilai nol hingga 63. Artinya, DSCP dapat digunakan pada antarmuka yang dirutekan Lapisan 3, dan lalu lintas dapat dipisahkan menjadi lebih banyak grup antrean, memberikan perincian yang lebih besar terkait prioritas lalu lintas.

CoS Class of Service - Revision history

Onnowpurbo at 00:37, 21 November 2022

Onnowpurbo: Created page with "Sumber: https://www.techtarget.com/searchnetworking/definition/Class-of-Service-CoS#:~:text=Class%20of%20Service%20(CoS)%20is,level%20of%20network%20service%20priority. Clas..."