ماذا تعني هذه الاوامر

[backtrack]

السلام عليكم

مثلاً لدي PC >>>>>> IP Phone >>>>>> switch

وهذه الاوامر على السويتش :

sw#conf t
sw(config)#mls qos
sw(config)#int fa 0/1
sw(config-if)#mls qos trust cos
sw(config-if)switchport voice vlan 10 dot1p
sw(config-if)#switchport priority cos 5
sw(config-if)#end

ممكن تعطوني شرح بسيط عن هذه الاوامر وخاصة هذا الامر sw(config-if)#switchport priority cos 5

وفقكم الله وسهل طريقكم

[Ehab_Salem]

تستخدم هذه الأوامر في ال QoS ووظيفتهم انهم يعطوا الvoice traffic أهمية أكبر عن ال data اللي بيطلع من ال PC

و بالنسبة لل command الأخير...هو غلط والمفروض يبقى
switchport priority extend cos 0

و أهميته انه يعطي ال data traffic اللي خارجة من ال PC أهمية صفر بالنسبة لل voice traffic اللي جي من ال IP Phone

[backtrack]

جزاك الله خير اخي

لكن الي مو راضي افهمه الرقم الذي بعد كلمة cos انا وجدته في Packet Tracer من 0-7 ماذا يمثل هذا الرقم

طيب انت تقول يعطى الاهمية 0 طيب لو جاء اي رقم غير الصفر مثلا 0او 2 ماذا تمثل

[backtrack]

وجدت الحل اخواني

Quote:

what difference does the number at the end of cos have?

switchport priority extend cos 0
switchport priority extend cos 2
switchport priority extend cos 3
switchport priority extend cos 4

That's a command for 802.1p

And you need to make sure you plug a PC into your Cisco IP Phone for it to have any effect.

A lot of places (like where I work) plug the phones into their own switch ports and give the PCs their own ports on a different VLAN. But if you're labbing it up for the CCNP, do it the Cisco way and connect the phone to a switch port and then plug the PC into your phone. I would also enable CDP (which you would most likely disable where you work) globally and on the ports.

The following is something I saved from an old Cisco web page. It may be slightly out of date, but I like the way they explain things:

The 802.1Q/p standard defines the use of the three-bit Class of Service (CoS) field in the 802.1Q tag to prioritize frames with eight classes (priorities) of traffic. The Cisco InterSwitch Link (ISL) trunk mode, which is also similar, provides the CoS field (least three significant bits in a four-bit user field). The Cisco IP phones, such as the Cisco 7960, tag the voice packets with a CoS value of five. These tagged packets are used by the switches to prioritize the voice traffic by queuing them in the priority queue in the egress port. This guarantees top priority to the time critical voice packets. Cisco switches do not provide any priority scheduling in the input side. However, they do provide priority scheduling in the output/egress port. The switches honor the incoming Class of Service (CoS) value in the dot1q tag. All the ports are considered trusted ports by default. Since dot1q does not tag the native VLAN traffic, issue the switchport priority default <0-7> interface level configuration command to classify the incoming untagged packet as desired. The switchport priority default <0-7> command is issued to provide CoS equivalent egress scheduling. If the egress port is a trunk port, the ingress CoS or port default priority configuration is marked in the outgoing frames as CoS values for the far-end device to treat them with the desired higher priority.

I'm not sure if you would get tested on ISL anymore, but the 802.1Q material should still be good.

[Ehab_Salem]

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