Shulou(Shulou.com)06/02 Report--

The following is an excerpt from the book "Huawei switch Learning Guide", which is being pre-sold by Dangdang and Jingdong. This book is the first and only authoritative learning guide for Huawei switch in China, and it is the designated textbook for Huawei ICT certification training, with nearly a thousand pages! Dangdang link: http://product.dangdang.com/23372225.html

JD.com link: http://item.jd.com/11355972.html

For booking this book, please refer to the lucky draw. For more information, click here: http://winda.blog.51cto.com/55153/1325503

5.1.2 Product support for iStack features

IStack is what we usually call "stacking", but the iStack function of Huawei switch is different from that of other manufacturers. In the latest Sx700 series, only the S2700, S3700, S5700 and S6700 series support iStack stacking, but not all models in these series support iStack, and the S2700Unix 3700 series does not have the same feature support for iStack as the S5700 Universe series. This section begins with a specific introduction.

S3700EI, S3700SI, S2700-52P-EI, S2700-52P-PWR-EI, and S2710SI are the subfamilies of switches that support stacking in the S2700Compact 3700 series, but switches in different subfamilies cannot be stacked mixed. The S3752EI and S3752SI subseries support up to 8 switch stacks, and other subseries products support up to 9 switch stacks. However, it should be noted that the S3752ei subseries switches cannot be stacked with the S3728ei subseries switches, and the S3752SI subseries switches cannot be stacked with the S3728SI subseries switches. That is, each member switch in the stack should not only have the same functional version, but also generally need the same number of ports.

The S5700 and S6700 series currently support the stacking of nine switches of the same model, and there can be no mixed stacking between different models of switches. The stacking connections supported by different models are described later in this section.

1. Stack primary and standby switch election

The iSack switch stacking system consists of several member switches, each of which has a defined role. When the stack is established, the member switches send stack competition messages to each other to elect the master and slave switches. When the VRP system software version number of the slave switch is not consistent with the VRP system software version of the master switch, the slave switch will automatically synchronize the VRP system software version of the master switch, reset and restart and join the stack system. The master switch collects member information and calculates the stack topology, and then synchronizes the stack topology information to all member switches.

The election rules for the primary switch are as follows:

(1) first of all, the running state of the stack switch is compared, and the switch that is the first to be in the startup state of the stack switch that is already running will be elected as the main switch.

(2) if more than one member switch is already in the startup state, the stack priority of these switches is compared, and the switch with high stack priority is selected as the main switch.

(3) if the stacking priority of some member switches is the same, then the MAC addresses of these member switches are compared, and the switches with small MAC addresses are selected as the main switch first.

The election rules for standby switches are as follows:

(1) the switch that is the first in the startup state of each member switch except the main switch becomes the backup switch.

(2) if multiple switches other than the main switch are started at the same time, the switch with the highest stacking priority among these member switches becomes the standby switch.

(3) if the stacking priority of these switches is the same, the minimum MAC address will be elected as the standby switch.

two。 Stacked connection mode

The iStack stack connections are not exactly the same for different small business switches. The S2700 and S3700 series mainly support stacking card connections through stacking ports provided in dedicated stacking cards (multiplex uplink gigabytes can also be used as stacking ports) and dedicated SFP high-speed stacking cables (connectors are 1.5 m long 20-pin SFP male, as shown in figure 5-2) (anti-static caps are required at both ends of the stacking cable plug).

Figure 5-2 SPF stacked cabl

The S5700 and S6700 series support the following two stacked connections:

L stacking card connection: each member switch is connected through a dedicated stacking card ETPC and a dedicated PCI-E stacking cable (1m in length, as shown in the figure on the left of figure 5-3). This connection is supported only by S5700EI and S5700SI subseries.

L service port connection: each member switch is connected to the stack physical member port and SFP+ high-speed cable through the stack port (as shown in the figure on the right of figure 5-3, the connector is a 20-pin SFP+ male, and the length can be 1m, 3m and 10m), and there is no need for a special stack card. This connection is supported only for S5700LI, S5710EI, and S6700 series.

The stacked connection methods and connection performance supported by the subseries of the S5700 and S6700 series are shown in Table 5-1.

Figure 5-3 PCI-E stacking cable and SFP+ stacking high-speed cable

Table 5-1 stacking connections supported by the subseries of the S5700 and S6700 series

Subseries

Stacking mode

Interfaces that support stacking

Stacked cable

Maximum stacking bandwidth (one-way)

Description

S5700-P-LI

(GE uplink model)

Service port stacking

V200R001 version: the last 2 SFP interfaces of the switch

V200R002 and later: the last 4 SFP interfaces of the switch

1m passive SFP+ cable

10m active SFP+ cable

Use 1m passive SFP+ cable for 2.5Gbit/s

Use 10m active SFP+ cable for 5Gbit/s

V200R001 version: a single switch supports up to 2 stack ports, each stack port contains up to 1 physical member port, and a single switch supports up to 2 physical member ports

V200R002 and later versions: a single switch supports up to 2 stack ports, each stack port contains up to 2 physical member ports, and a single switch supports up to 4 physical member ports

Support mixing between GE uplink models, but not between GE uplink models and 10GE uplink models

S5700-10P-LI-AC and S5700-10P-PWR-LI-AC do not support stacking

S5700-X-LI

(10GE uplink model)

Service port stacking

The last four SFP+ interfaces of the switch

1m/3m passive SFP+ cable, 10m active SFP+ cable, ordinary SFP+ optical module and optical fiber

10Gbit/s

A single switch supports up to 2 stack ports, each stack port contains up to 2 physical member ports, and a single switch supports up to 4 physical member ports

Support mixing between 10GE uplink models, but not between GE uplink models and 10GE uplink models

S5700-SI

Stacking card stacking

Two stacking ports of stacked cards

1m PCIe cable

12Gbit/s

All PoE and non-PoE hybrids that support S5700-SI

S5700-26X-SI-12S-AC does not support stacking

S5700-EI

Stacking card stacking

Two stacking ports of stacked cards

PCIe cable for 1m/3m

12Gbit/s

Only S5700-52C-EI and S5700-28C-EI-24S are supported, but all PoE and non-PoE hybrids of S5700-EI are supported

S5710-EI

Service port stacking

Any 10GE interface on the switch: including the 4 fixed SFP+ interfaces in front of the switch and the rear SFP+ card

1m/3m passive SFP+ cable, 10m active SFP+ cable, ordinary SFP+ optical module and optical fiber

10Gbit/s

V200R001 version: a single switch supports up to 2 stack ports, each stack port contains up to 3 physical member ports, and a single switch supports up to 4 physical member ports. The physical member port distribution of all stack ports must be on the front panel or all on the rear plug-in card.

V200R002 and later versions: a single switch supports up to 2 stack ports, each stack port contains up to 4 physical member ports, and a single switch supports up to 8 physical member ports

All models that support S5710-EI are mixed.

S6700

Service port stacking

Any 10GE interface on the switch. Up to 8 simultaneous interfaces for stacking

1m/3m/10m passive SFP+ cable, 10m active SFP+ cable (supported by V200R001C00 version and later), ordinary SFP+ optical module and optical fiber

10Gbit/s

All models that support S6700 are mixed with each other, and the interface does not support stacking when working in GE mode.

S5700-HI and S5700S-LI subseries currently do not support stacking

3. Stack connection topology

The connection topology of Huawei S-Series switch iStack stack has two kinds of "chain connection" and "ring connection". The ring connection topology is that the member switches of the stack are connected by * * forks at the end of the stack to form a "ring" structure, as shown in figure 5-4.

Figure 5-4 iStack stacked ring topology

In the chain connection topology, the switches at both ends of the chain are connected to neighboring switches using only one stack port, resulting in a "chain" structure (a bit like a switch "cascade"), as shown in figure 5-5. In contrast, the ring connection topology is more reliable than the chain connection topology, because it will cause stack splitting when a link failure occurs in the chain connection topology. on the other hand, when a link in the ring connection topology fails, a chain connection will be formed, and the overall stacked business will not be affected. Therefore, it is recommended that the ring topology be used in the actual deployment of the business.

Figure 5-5 iStack stacked chain topology

4. Stack management and maintenance

After the iStack stack is established, all member switches form a logical switch and exist in the network, and the resources of all member switches are uniformly managed by the stack master switch. Users can log in to the stacking system through the network management interface or serial port of any member switch to manage and maintain the whole stacking system. But only one network management interface or serial port can log in at the same time.

In addition, there are some differences in interface numbers when managing member switches in a stack and when managing individual switches. For a single switch that is not running stacking, the interface number is: 0 / daughter card number / port number, while after the switch is added to the stack, the interface number is: stacked ID/ daughter card number / port number. If the switch is not running a stack, the number of an interface is GigabitEthernet0/0/1;. After the switch joins the stack, if the stack ID assigned to the switch is 2, the number of the interface will become GigabitEthernet2/0/1. In this way, each interface number in the entire stack switch is unique.

5. Stack member join

Topology collection continues during the maintenance and use of the iStack stack, and when a new member switch (with stacking connection and stacking features configured) is found to have joined, it will be handled differently according to the status of the newly added switch:

If the newly added switch itself does not form a stack, the newly added switch will be selected as the slave switch, and the original master and standby roles in the stacking system will remain unchanged.

If the newly added switch itself has formed a stack, it is equivalent to the merger of the two stacks. In this case, the master switch of the two stacking systems will elect a better switch as the primary switch of the new stacking system, and one of the stacking systems (the stacking system where the new primary switch resides) will remain unchanged and the business will not be affected; while all switches of the other stacking system will be rebooted and added to the new stack, the configuration of the primary switch will be synchronized, and the original business of the stack will be interrupted.

6. Stack member exit

IStack stack member exit means that the member switch leaves the stack system and disconnects the stack connection. The impact on the stacking system varies depending on the role of the exiting member. The details are as follows:

Exit primary switch: upgrade the standby switch to the primary switch, update the stack topology and specify a new standby switch.

L standby switch exit: the primary switch updates the stack topology and specifies a new standby switch.

Exit from the switch: the primary switch updates the stack topology.

7. Stacking master, standby switching and stacking system MAC address switching

When the iStack stacking system is successfully established, if the primary switch fails or breaks away from the stacking system, the standby switch is automatically promoted to the primary switch, and then the new master switch appoints a new standby switch, and the master and standby switches synchronize data. Here, the switching of the stacking master and slave, and the switching of the MAC address of the stacking system need to distinguish between the following three situations:

When the stacking system is successfully established for the first time, the MAC address of the stacking system is the MAC address of the primary switch. When the primary switch fails or leaves the stacking system, the system MAC address will immediately switch to the MAC address of the new primary switch in the case of delaying switching of the MAC address of the stacking system. The default enables stacking system MAC address delay switching function, the delay time is 10 minutes.

When the stacking system is successfully established, if the primary switch fails or leaves the stacking system, if the stacking system is configured with a system MAC address switching time, and the old primary switch has not rejoined the stacking system within the switching timer timeout, the new primary switch switches the MAC address of the stacking system to its own MAC address. Conversely, if the old master switch rejoins the stack within the handover timer timeout, the old master switch of the system becomes a slave switch, but the MAC address of the stacking system does not switch. In this case, the MAC address of the stacking system is the MAC address of the slave switch.

When there is a slave in the stacking switch, if the MAC address of the slave switch is the stacked system MAC address (as in the case above), and the switch does not rejoin the stack within the switching timer timeout, the master switch switches the stacking system MAC address to its own MAC address.

However, it should be noted that frequent active / standby switching may lead to stack splitting.

8. Stack splitting

IStack stack splitting refers to the electrified removal of some member switches in a steady-state stacking system, or multipoint failure of the stacking cable causes one stacking system to become multiple stacking systems, as shown in figure 5-6. After the stacking system is split, multiple stacking systems with the same configuration may be produced, which will lead to the conflict between IP address and MAC address in the network, and cause network failure.

Figure 5-6 schematic diagram of stack splitting

9. Double master detection

Dual primary detection DAD (Dual-Active Detection) is a protocol for detecting and handling stack splits, which can realize stack split detection, conflict handling and fault recovery, and reduce the impact of stack splits on business. Only S5700 and S6700 series support, and only support the stack system composed of two switches.

There are two main detection methods: directly connected detection mode and Relay proxy detection mode.

L directly connected detection mode

As shown in figure 5-7, dual master detection is carried out between the stack member switches through a dedicated directly connected link. In the directly connected detection mode, when the stack system is running normally, the DAD message is not sent in order to reduce the CPU burden; after the stack system is split, the stack member switch sends the DAD message through the detection link in a period of 1 second.

Fig. 5-7 schematic diagram of dual-master detection in directly connected mode

L Relay agent detection mode

As shown in figure 5-8, the Relay proxy detection method enables DAD detection on the stacking system across switch Eth-Trunk and the DAD proxy feature on the proxy switch. The proxy switch must be a switch that supports the DAD Relay proxy function, which is currently supported by all small Business switches.

Figure 5-8 schematic diagram of dual-master detection in Relay proxy mode

In the Relay agent detection mode, when the stack system is running normally, the stack member switch sends DAD messages through the detection link in a period of 30 seconds. The stack member switch does not do any processing to the DAD message received in the normal working state; after the stack system is split, the stack member switch sends the DAD message through the detection link in a period of 1 second.

After the stack is split, the stack system that is split into multiple parts will send DAD contention messages to each other on the detection link. The stacking system compares the message information received with this part of the competition information: if this part competes for the main switch, it will not deal with it, keep the Active state, and forward the service message normally; if this part competes for the standby switch, it needs to close all the service ports except the reserved port (the port on the switch that will not be closed), transfer to the Recovery state, and stop forwarding the service message. After the stack link is repaired, the stack in the Recovery state will be restarted, the closed service port will be restored to Up, and the entire stack system will be restored.

Welcome to subscribe "Shulou Technology Information " to get latest news, interesting things and hot topics in the IT industry, and controls the hottest and latest Internet news, technology news and IT industry trends.