84
C
HAPTER
9: VLAN C
ONFIGURATION
Figure 25
A VLAN diagram
A VLAN is not restricted by physical factors, that is to say, hosts that reside in
different network segments may belong to the same VLAN, users in a VLAN can
be connected to the same switch, or span across multiple switches or routers.
VLAN technology has the following advantages:
1
Broadcast traffic is confined to each VLAN, reducing bandwidth utilization and
improving network performance.
2
LAN security is improved. Packets in different VLANs are isolated at Layer 2. That
is, users in a VLAN cannot communicate with users in other VLANs directly, unless
routers or Layer 3 switches are used.
3
A more flexible way to establish virtual workgroups. With VLAN technology, a
virtual workgroup can be created spanning physical network segments. That is,
users from the same workgroup do not have to be within the same physical area,
making network construction and maintenance much easier and more flexible.
VLAN Fundamental
To enable packets being distinguished by the VLANs they belong to, The VLAN tag
fields used to identify VLANs are added to packets. As common switches operate
on the data link layer of the OSI model, they only process data link layer
encapsulation information and the VLAN tag thus needs to be inserted to the data
link layer encapsulation.
The format of the packets carrying the VLAN tag fields is defined in IEEE 802.1Q,
which is issued by IEEE in 1999.
In the header of a traditional Ethernet data frame, the field following the
destination MAC address and the source MAC address is the Type field, which
indicates the upper layer protocol type. Figure 26 illustrates the format of a
traditional Ethernet frame, where DA stands for destination MAC address, SA
stands for source MAC address, and Type stands for the upper layer protocol type
of the frame.
Figure 26
The format of a traditional Ethernet frame
VLAN 2
VLAN 5
Switch B
Switch A
Router
Type
Data
DA&SA
Содержание 4800G Series
Страница 26: ...26 CHAPTER NETWORKING APPLICATIONS ...
Страница 30: ...30 CHAPTER 1 LOGGING IN TO AN ETHERNET SWITCH ...
Страница 62: ...62 CHAPTER 3 LOGGING IN THROUGH TELNET ...
Страница 70: ...70 CHAPTER 5 LOGGING IN THROUGH WEB BASED NETWORK MANAGEMENT SYSTEM ...
Страница 72: ...72 CHAPTER 6 LOGGING IN THROUGH NMS ...
Страница 82: ...82 CHAPTER 8 CONTROLLING LOGIN USERS ...
Страница 98: ...98 CHAPTER 9 VLAN CONFIGURATION ...
Страница 108: ...108 CHAPTER 10 VOICE VLAN CONFIGURATION ...
Страница 119: ...GVRP Configuration Examples 119 DeviceB display vlan dynamic No dynamic vlans exist ...
Страница 120: ...120 CHAPTER 11 GVRP CONFIGURATION ...
Страница 160: ...160 CHAPTER 17 PORT ISOLATION CONFIGURATION ...
Страница 172: ...172 CHAPTER 19 LINK AGGREGATION CONFIGURATION ...
Страница 196: ...196 CHAPTER 22 DLDP CONFIGURATION ...
Страница 240: ...240 CHAPTER 23 MSTP CONFIGURATION ...
Страница 272: ...272 CHAPTER 27 RIP CONFIGURATION ...
Страница 364: ...364 CHAPTER 29 IS IS CONFIGURATION ...
Страница 426: ...426 CHAPTER 31 ROUTING POLICY CONFIGURATION ...
Страница 442: ...442 CHAPTER 33 IPV6 RIPNG CONFIGURATION ...
Страница 466: ...466 CHAPTER 35 IPV6 IS IS CONFIGURATION ...
Страница 488: ...488 CHAPTER 36 IPV6 BGP CONFIGURATION ...
Страница 498: ...498 CHAPTER 37 ROUTING POLICY CONFIGURATION ...
Страница 540: ...540 CHAPTER 40 TUNNELING CONFIGURATION ...
Страница 552: ...552 CHAPTER 41 MULTICAST OVERVIEW ...
Страница 604: ...604 CHAPTER 43 MLD SNOOPING CONFIGURATION ...
Страница 628: ...628 CHAPTER 46 IGMP CONFIGURATION ...
Страница 699: ...Troubleshooting MSDP 699 4 Verify that the C BSR address is different from the anycast RP address ...
Страница 700: ...700 CHAPTER 48 MSDP CONFIGURATION ...
Страница 812: ...812 CHAPTER 57 DHCP SERVER CONFIGURATION ...
Страница 822: ...822 CHAPTER 58 DHCP RELAY AGENT CONFIGURATION ...
Страница 834: ...834 CHAPTER 61 BOOTP CLIENT CONFIGURATION ...
Страница 850: ...850 CHAPTER 63 IPV4 ACL CONFIGURATION ...
Страница 856: ...856 CHAPTER 64 IPV6 ACL CONFIGURATION ...
Страница 860: ...860 CHAPTER 65 QOS OVERVIEW ...
Страница 868: ...868 CHAPTER 66 TRAFFIC CLASSIFICATION TP AND LR CONFIGURATION ...
Страница 888: ...888 CHAPTER 69 PRIORITY MAPPING ...
Страница 894: ...894 CHAPTER 71 TRAFFIC MIRRORING CONFIGURATION ...
Страница 904: ...904 CHAPTER 72 PORT MIRRORING CONFIGURATION ...
Страница 930: ...930 CHAPTER 74 UDP HELPER CONFIGURATION ...
Страница 990: ...990 CHAPTER 79 FILE SYSTEM MANAGEMENT CONFIGURATION ...
Страница 1000: ...1000 CHAPTER 80 FTP CONFIGURATION ...
Страница 1020: ...1020 CHAPTER 82 INFORMATION CENTER CONFIGURATION ...
Страница 1038: ...1038 CHAPTER 84 SYSTEM MAINTAINING AND DEBUGGING ...
Страница 1046: ...1046 CHAPTER 85 DEVICE MANAGEMENT ...
Страница 1129: ...SSH Client Configuration Examples 1129 SwitchB ...
Страница 1130: ...1130 CHAPTER 88 SSH CONFIGURATION ...
Страница 1160: ...1160 CHAPTER 90 RRPP CONFIGURATION ...
Страница 1180: ...1180 CHAPTER 91 PORT SECURITY CONFIGURATION ...
Страница 1192: ...1192 CHAPTER 92 LLDP CONFIGURATION ...
Страница 1202: ...1202 CHAPTER 93 POE CONFIGURATION ...
Страница 1218: ...1218 CHAPTER 96 HTTPS CONFIGURATION ...