the SmartCast question

why we need to open the classification and marking together?
because incoming traffic needs classification first, before continue to marking (for outgoing traffic)
When the marking will work?
marking is the action that you want to change tos/dot1p value for outgoing traffic L3 packets always have ToS field, that you always can mark with ToS value

Why we have ToS nonzero Marking this function?
L3 packets always have ToS field

If you want insert a packet to voice queue
1. packet will match with heuristics rule for voice (mean matching packet gap and packet length)
2. packet can be matched voice TOS value
3. packet can match Port matching filter rule...

packet from queue want to go out
you have 2 ways to process with it:
1. You don't want to change anything, just leaving(traffic will not change anything)
2. You want to change tos value (or dot1p value)

you know why we only mark using tos/dot1p value
because that a field using for QoS
we only classify packet based on the ToS filed (or dot1p filed), because the purpose of that field is for QoS

How many string we can have?

The string is depend on bandwidth.

IPTV業務一般提供2種不同類型的電視業務：標準解析度(SD)和高解析度電視(HDTV)，而SDTV頻寬在 1Mbps到4Mbps之間，HDTV頻寬則在4Mbps到13Mbps之間。
服務供應商通常能提供數十個電視訊號頻道，外加10到20個HDTV頻道， 在歐美國家頻道數量甚至可達數倍以上；如果1個家庭具有大約3台電視，其中包含2台標準解析度電視， 1台高解析度電視，而且都接入IPTV服務的話，一般大約20Mbps左右的頻寬就可以支援這些電視，當電視數目增加，可能還要再往上增加。因此，到家庭 的不同串流的頻寬管理是至關重要的問題，即語音、資料和視訊業務需要個別處理。

IPTV

1. When will the marking function take effect ?

[Leon]: In CLI, when you type “set qos eth1 tos mark enable”, the mark function will be enabled on eth1. As you type “get qos eth1”, you will see

TOS Marking: Enabled

Currently, dot1p mark has some problem. So I just talk about TOS at this time.

Enabling tos mark on eth1 means that when an AP sees a voice|video|data|Background packet on its ingress eth1 port, the packet will be marked as the desired TOS value as shown below.

TOS marking: VoIP=0xE0, Video=0xA0, Data=0x18, Background=0x20

For the above example, each voice packet the AP sees will be marked a TOS value with 0xE0.

2. The TOS and 802.1p marking function will re-mark the original tos field for down/up link ?
ex:

wireless client ))) ((( AP-----remote host

(zing client -q0x30) <--------------- (zing --server -q0x30)

[Leon] In your example, it is not the marking process. It looks like the process of TOS classification. If we type “set qos tos classification enable”, then each time the AP sees the TOS value in the packet shown below,

TOS Classification: Voice=0xE0,0xC0,0xB8, Video=0xA0,0x80, Data=none, Background=none,

then the packet will be classified into voice|video|Data|Background according to the above TOS values. This looks like the revert function of TOS marking.

3. I have tried to disable "UDP Heuristic Classification" , and I don't know what the rules of smartcast will be follow.

UDP Heuristic Classification is not that easy to describe. But roughly speaking, “UDP Heuristic Classification” is the process to classify a packet for UDP unicast packet. To disable UDP Heuristic Classification means that if your packet is not previous classified and has no TOS/dot1p value on it, the packet will be regarded as default priority, i.e., data. If you enable it, then you got a chance to classify to the proper priority.

IGMP Packet Format

1, IGMP V1: 支持包类型, 两种 query 和report; router 等待超时时间才知道组成员已经不存在;
2,IGMP V2: 支持包类型, 三种, query,report和Leave, 增加Leave包的目的是,当组中最后一个成员离开时,通知路由器,快速收敛. 而且Query包也分为两种, 一为正常的Query,查询所有的组是否有成员(类似于V1);一种为特殊的query,在收到Leave包后, 路由器所发出的只查询该组的query包;
3,IGMP V3: 支持包的类型,两种, query和report. 增加Source filtering功能, host可以通知路由器,指定只收或者不收,某些特定的组和原地址的包. 防止了Unkonw host的DOS攻击. query分为三种, 查询所有组的/特殊组的/特殊组和特殊源地址的;
关于V3为什么要取消Leave这个有助于快速收敛的包呢? 其实他将V2的Leave包的功能加入到report包中来了, 当host有任何变动且认为应该通知Router时,他就会发送report包.
http://www.commsdesign.com/showArticle.jhtml?articleID=52200253
224.0.0.0 － Base address
224.0.0.1 － 网段中所有支持多播的主机
224.0.0.2 － 网段中所有支持多播的路由器
224.0.0.4 － 网段中所有的DVMRP路由器
224.0.0.5 － 所有的OSPF路由器
224.0.0.6 － 所有的OSPF指派路由器
224.0.0.7 － 所有的ST路由器
224.0.0.8 － 所有的ST主机
224.0.0.9 － 所有RIPv2路由器
224.0.0.10 － 网段中所有支的路由器
224.0.0.11 － Mobile-Agents
224.0.0.12 － DHCP server / relay agent.
224.0.0.13 － 所有的PIM路由器
224.0.0.22 － 所有的IGMP路由器
224.0.0.251 － 所有的支持组播的DNS服务器