參數(shù)資料
型號(hào): MVTX2603
廠商: Zarlink Semiconductor Inc.
英文描述: Unmanaged 24-Port 10/100 Mb + 2-Port 1 Gb Ethernet Switch
中文描述: 非托管的24端口的10/100 Mb 2端口千兆以太網(wǎng)交換機(jī)1
文件頁數(shù): 17/109頁
文件大?。?/td> 803K
代理商: MVTX2603
MVTX2603
Data Sheet
17
Zarlink Semiconductor Inc.
5.2 Basic Flow
Shortly after a frame enters the MVTX2603 and is written to the Frame Data Buffer (FDB), the frame engine
generates a Switch Request, which is sent to the search engine. The switch request consists of the first 64 bytes of
the frame, which contain all the necessary information for the search engine to perform its task. When the search
engine is done, it writes to the Switch Response Queue, and the frame engine uses the information provided in that
queue for scheduling and forwarding.
In performing its task, the search engine extracts and compresses the useful information from the 64-byte switch
request. Among the information extracted are the source and destination MAC addresses, the transmission and
discard priorities, whether the frame is unicast or multicast. Requests are sent to the external SRAM to locate the
associated entries in the external hash table.
When all the information has been collected from external SRAM, the search engine has to compare the MAC
address on the current entry with the MAC address for which it is searching. If it is not a match, the process is
repeated on the internal MCT Table. All MCT entries other than the first of each linked list are maintained internal to
the chip. If the desired MAC address is still not found, then the result is either learning (source MAC address
unknown) or flooding (destination MAC address unknown).
In addition, port based VLAN information is used to select the correct set of destination ports for the frame (for
multicast) or to verify that the frame’s destination port is associated with the VLAN (for unicast).
If the destination MAC address belongs to a port trunk, then the trunk number is retrieved instead of the port
number. But on which port of the trunk will the frame be transmitted This is easily computed using a hash of the
source and destination MAC addresses.
As stated earlier, when all the information is compiled the switch response is generated.
5.3 Search, Learning, and Aging
5.3.1 MAC Search
The search block performs source MAC address and destination MAC address searching. As we indicated earlier,
if a match is not found, then the next entry in the linked list must be examined, and so on until a match is found or
the end of the list is reached.
The port based VLAN bitmap is used to determine whether the frame should be forwarded to the outgoing port.
When the egress port is not included in the ingress port VLAN bitmap, the packet is discarded.
The MAC search block is also responsible for updating the source MAC address timestamp and the VLAN port
association timestamp, used for aging.
5.3.2 Learning
The learning module learns new MAC addresses and performs port change operations on the MCT database. The
goal of learning is to update this database as the networking environment changes over time. Learning and port
change will be performed based on memory slot availability only.
5.3.3 Aging
Aging time is controlled by register 400h and 401h.
The aging module scans and ages MCT entries based on a programmable “age out” time interval. As we indicated
earlier, the search module updates the source MAC address timestamps for each frame it processes. When an
entry is ready to be aged, the entry is removed from the table.
相關(guān)PDF資料
PDF描述
MVTX2603AG Unmanaged 24-Port 10/100 Mb + 2-Port 1 Gb Ethernet Switch
MVTX2604 Managed 24-Port 10/100 Mb + 2 Port 1 Gb Ethernet Switch
MVTX2604AG Managed 24-Port 10/100 Mb + 2 Port 1 Gb Ethernet Switch
MVTX2801 Unmanaged 4-Port 1000 Mbps Ethernet Switch
MVTX2801AG Unmanaged 4-Port 1000 Mbps Ethernet Switch
相關(guān)代理商/技術(shù)參數(shù)
參數(shù)描述
MVTX2603A 制造商:未知廠家 制造商全稱:未知廠家 功能描述:Unmanaged 24 port 10/100Mb + 2 port 1Gb Ethernet switch
MVTX2603AG 制造商:ZARLINK 制造商全稱:Zarlink Semiconductor Inc 功能描述:Unmanaged 24-Port 10/100 Mb + 2-Port 1 Gb Ethernet Switch
MVTX2603AG2 制造商:Microsemi Corporation 功能描述:
MVTX2604 制造商:ZARLINK 制造商全稱:Zarlink Semiconductor Inc 功能描述:Managed 24-Port 10/100 Mb + 2 Port 1 Gb Ethernet Switch
MVTX2604A 制造商:未知廠家 制造商全稱:未知廠家 功能描述:MVTX260x Physical Port Control