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Chapter 5 WAN Setup
P-2812HNU-51c User’s Guide
116
contains two bytes of TPID (Tag Protocol Identifier), residing within the type/
length field of the Ethernet frame) and two bytes of TCI (Tag Control Information),
starts after the source address field of the Ethernet frame).
The CFI (Canonical Format Indicator) is a single-bit flag, always set to zero for
Ethernet switches. If a frame received at an Ethernet port has a CFI set to 1, then
that frame should not be forwarded as it is to an untagged port. The remaining
twelve bits define the VLAN ID, giving a possible maximum number of 4,096
VLANs. Note that user priority and VLAN ID are independent of each other. A
frame with VID (VLAN Identifier) of null (0) is called a priority frame, meaning that
only the priority level is significant and the default VID of the ingress port is given
as the VID of the frame. Of the 4096 possible VIDs, a VID of 0 is used to identify
priority frames and value 4095 (FFF) is reserved, so the maximum possible VLAN
configurations are 4,094.
Multicast
IP packets are transmitted in either one of two ways - Unicast (1 sender - 1
recipient) or Broadcast (1 sender - everybody on the network). Multicast delivers
IP packets to a group of hosts on the network - not everybody and not just 1.
Internet Group Multicast Protocol (IGMP) is a network-layer protocol used to
establish membership in a Multicast group - it is not used to carry user data. IGMP
version 2 (RFC 2236) is an improvement over version 1 (RFC 1112) but IGMP
version 1 is still in wide use. If you would like to read more detailed information
about interoperability between IGMP version 2 and version 1, please see sections
4 and 5 of RFC 2236. The class D IP address is used to identify host groups and
can be in the range 224.0.0.0 to 239.255.255.255. The address 224.0.0.0 is not
assigned to any group and is used by IP multicast computers. The address
224.0.0.1 is used for query messages and is assigned to the permanent group of
all IP hosts (including gateways). All hosts must join the 224.0.0.1 group in order
to participate in IGMP. The address 224.0.0.2 is assigned to the multicast routers
group.
At start up, the P-2812HNU-51c queries all directly connected networks to gather
group membership. After that, the P-2812HNU-51c periodically updates this
information.
DNS Server Address Assignment
Use Domain Name System (DNS) to map a domain name to its corresponding IP
address and vice versa, for instance, the IP address of www.zyxel.com is
TPID
2 Bytes
User Priority
3 Bits
CFI
1 Bit
VLAN ID
12 Bits
Содержание P-2812HNU-51c
Страница 2: ......
Страница 8: ...Safety Warnings P 2812HNU 51c User s Guide 8 ...
Страница 10: ...Contents Overview P 2812HNU 51c User s Guide 10 ...
Страница 19: ...19 PART I User s Guide ...
Страница 20: ...20 ...
Страница 73: ...73 PART II Technical Reference ...
Страница 74: ...74 ...
Страница 88: ...Chapter 4 Status Screens P 2812HNU 51c User s Guide 88 ...
Страница 118: ...Chapter 5 WAN Setup P 2812HNU 51c User s Guide 118 ...
Страница 204: ...Chapter 9 Voice P 2812HNU 51c User s Guide 204 ...
Страница 210: ...Chapter 10 File Sharing P 2812HNU 51c User s Guide 210 ...
Страница 216: ...Chapter 11 Firewall P 2812HNU 51c User s Guide 216 ...
Страница 223: ...Chapter 12 Certificate P 2812HNU 51c User s Guide 223 Figure 99 Certificate Details ...
Страница 232: ...Chapter 13 Static Route P 2812HNU 51c User s Guide 232 ...
Страница 236: ...Chapter 14 Policy Forwarding P 2812HNU 51c User s Guide 236 ...
Страница 252: ...Chapter 16 Quality of Service QoS P 2812HNU 51c User s Guide 252 ...
Страница 274: ...Chapter 19 Universal Plug and Play UPnP P 2812HNU 51c User s Guide 274 ...
Страница 284: ...Chapter 21 Interface Group P 2812HNU 51c User s Guide 284 ...
Страница 288: ...Chapter 22 System Settings P 2812HNU 51c User s Guide 288 ...
Страница 292: ...Chapter 23 Logs P 2812HNU 51c User s Guide 292 ...
Страница 300: ...Chapter 24 Tools P 2812HNU 51c User s Guide 300 ...
Страница 320: ...Chapter 27 Product Specifications P 2812HNU 51c User s Guide 320 ...
Страница 336: ...Appendix A Network Troubleshooting P 2812HNU 51c User s Guide 336 ...
Страница 376: ...Appendix C Pop up Windows JavaScripts and Java Permissions P 2812HNU 51c User s Guide 376 ...
Страница 388: ...Appendix D IP Addresses and Subnetting P 2812HNU 51c User s Guide 388 ...