Chapter 8. Bandwidth Management

This chapter covers the following topics:

Images Subzone Bandwidth Management: This topic will explain how Subzones can be used to manage bandwidth for calls through the Cisco Expressway.

Images Links and Pipes Bandwidth Management: This topic will explain how to use an alternative means of managing bandwidth using Pipes to throttle calls across Links on the Cisco Expressway.

Images Call Control using Pipes: This topic will examine how Pipes can be used for call control across an Expressway, and not just for bandwidth management.

Chapter 7, “Configure Expressway Core Dial Plan Elements,” examined how call control on the Cisco Expressway can be managed using pre-search tools, such as Transforms, Call Policy and User Policy. That chapter also briefly discussed how call control can be implemented using Transforms within Search Rules. However, one of the most significant means of administering call control is through bandwidth management. While the Cisco Unified CM uses Regions and Locations to administer bandwidth management, the Cisco Expressway uses Subzones and Pipes. This chapter will provide you with a thorough understanding what these tools are, how they work and how they can be configured to control bandwidth from within the Cisco Expressway.

This chapter covers the following objectives from the Implementing Cisco Collaboration Cloud and Edge Solutions (CLCEI) exam 300-820:

Images 1.7.e Describe Expressway Core dial plan elements: Pipes and links

Images 2.2.e Configure Expressway Core Dial Plan Elements: Pipes and links

“Do I Know This Already?” Quiz

The “Do I Know This Already?” quiz allows you to assess whether you should read this entire chapter thoroughly or jump to the “Exam Preparation Tasks” section. If you are in doubt about your answers to these questions or your own assessment of your knowledge of the topics, read the entire chapter. Table 8-1 lists the major headings in this chapter and their corresponding “Do I Know This Already?” quiz questions. You can find the answers in Appendix A, “Answers to the ‘Do I Know This Already?’ Quizzes.”

Table 8-1 ”Do I Know This Already?” Section-to-Question Mapping

Images

Caution

The goal of self-assessment is to gauge your mastery of the topics in this chapter. If you do not know the answer to a question or are only partially sure of the answer, you should mark that question as wrong for purposes of the self-assessment. Giving yourself credit for an answer you correctly guess skews your self-assessment results and might provide you with a false sense of security.


1. In which of the following methods can bandwidth be applied to calls from the Cisco Expressway?

a. Total bandwidth only

b. Within and total

c. In and out and total

d. per call and total

2. In which of the following scenarios would the In and Out bandwidth restriction be used in Subzones?

a. Calls between two H.323 endpoints within the same Subzone

b. Calls between two SIP endpoints within the same Subzone

c. Calls between an H.323 and SIP endpoint within the same Subzone

d. Calls between an H.323 and SIP endpoint within the same Traversal Subzone

3. Which of the following best describe the purpose of the Default Call Bandwidth setting on the Cisco Expressway?

a. Sets the maximum bandwidth allowed per call across the Expressway by default.

b. Sets the maximum total bandwidth allowed across the Expressway by default.

c. Applies a default bandwidth rate to all calls that don’t request a limit.

d. Applies bandwidth settings to all calls by default regardless of the requested limit when enabled.

4. Which of the following can be used to restrict bandwidth within the Cisco Expressway?

a. Links

b. Pipes

c. Zones

d. Default Zone

5. How many Links can a single Pipe be applied to on the Cisco Expressway?

a. No Limit

b. One Link

c. Two Links

d. Ten Links

6. How many Pipes can be applied to a single Link on the Cisco Expressway?

a. No Limit

b. One Pipe

c. Two Pipes

d. Ten Pipes

7. Which of the following statements is true regarding how the Cisco Expressway processes calls?

a. If a call between two subzones is blocked, the call will re-route along another path.

b. If a call between a Zone and a subzone is blocked, the call will re-route along another path.

c. All calls will follow the shortest path. If that path is blocked, then the call will re-route to the next shortest path.

d. All calls will follow the shortest path. If that path is blocked, then the call will fail.

Foundation Topics

Subzone Bandwidth Management

Chapter 7 began by introducing you to the call processing order, which is the order every call attempt through Expressway will be executed. Before the Expressway begins to search for the dialed alias, it will go through a pre-search checklist. The first things the Expressway will check are Transforms, then Call Policy and finally User Policy. Once the Expressway has completed the Pre-search criteria, it will then begin the search through Zones. Searches are performed based on the priority of the search rules. If endpoints are registered to the Expressway the first Zone that should be searched is the Local Zone. If no match is found, then external Zones should be searched. After the Expressway locates the dialed endpoint, the last item the Expressway will check within the call processing order is whether any Bandwidth Restrictions have been configured that need to be applied to this call, and if so, if there’s any available bandwidth to allow the call to proceed. Figure 8-1 illustrates the two ways bandwidth restrictions can be applied to calls through the Expressway.

Images

Figure 8-1 Bandwidth Restriction Options on the Expressway

As seen in Figure 8-1, there are two methods for implementing bandwidth restrictions on an Expressway; using Pipes or Subzones. Using either of these methods, bandwidth restrictions can be applied to the call in two ways; on a “per-call” basis, and “total bandwidth.” Per call restrictions are applied to every call attempt on an independent basis. Total bandwidth restrictions take the culmination of all concurrent calls in progress and allow or restrict calls based on that total accumulative value. This per call and total bandwidth value is evident in the Traversal Subzone, since no devices will ever register to this subzone.

Because the default subzone, or any other created subzone, possess the ability to host device registration, the per-call bandwidth restriction is divided into two categories; “Within” and “In & out.” “Within” restrictions control the bandwidth that is used between two devices that are registered to the same subzone. “In & out” restrictions control the bandwidth that is used when the call flow must travel outside of the subzone.

Images

The following list are examples of when In & Out restrictions are used:

Images When a call is placed between two endpoints that are registered to different subzones in the same Expressway.

Images When a call is placed between an endpoint registered to the Expressway and another call control device such as the CUCM. This would also include B2B and B2C calls.

Images When a call is placed between two endpoints that are registered to the same subzones, but the call must be interworked using the Traversal Subzone, such as a call between a SIP and H.323 endpoint.

Images

When configuring the bandwidth restrictions, there are three limitation modes:

Images None(No Bandwidth): no bandwidth is allocated and therefore no calls can be made.

Images Limited: limits are applied according to the value set in the bandwidth (kbps) field.

Images Unlimited: no restrictions will be applied to the amount of bandwidth being used.

Now that basic parameters have been established for how bandwidth restrictions need to be configured for subzones, the following scenarios will explain the behavior of the Cisco Expressway when executing Subzone bandwidth restrictions. Figure 8-2 illustrates how bandwidth restrictions can be applied to Subzones. This figure will be used to explain several call scenarios.

Images

Figure 8-2 Bandwidth Restrictions using Subzones

In the previous figure there are three subzones, and each subzone has been assigned various bandwidth restrictions with endpoints registered to them. Obviously, you would not use bandwidth restrictions this low in a production environment. I only used low bandwidth rates to better illustrate how bandwidth restrictions work within subzones. For example, if endpoint 4001 calls endpoint 4002 at 768 kbps, the call would go through as dialed without issues. Both endpoints are registered to the same Subzone and the bandwidth limitation for calls within the Default Subzone is 768 kb/s.

Now let’s examine call behavior for a call attempt outside the allowed bandwidth restrictions illustrated in Figure 8-2. Imagine endpoint 4001 calls endpoint 4002 at 2 Mbps. As examined previously, both endpoints are registered to the same subzone but the bandwidth limitation for calls within that subzone is 768 kbps. Therefore, the call would either fail or down speed, depending on how the down speed settings are configured within the Cisco Expressway. To Configure the Downspeed Mode setting navigate to Configuration > Bandwidth > Configuration. Figure 8-3 illustrates these bandwidth settings on the Cisco Expressway.

Images

Figure 8-3 Bandwidth Downspeed Mode

There are three settings in Figure 8-3 that need some explanation. The first and often the most confusing setting is the Default Call Bandwidth. This bandwidth setting is not a limitation. Some endpoints allow the internal bandwidth setting to be auto negotiated. If one of those endpoints were to place a call and not specify the desired bandwidth, the Expressway will implement whatever limit has been established here. The default value is 384 kbps, but this setting can be changed to whatever limit is desired. If this limit is set to a high rate, such as 2048 Mbps, and there are bandwidth restrictions set in subzones or pipes that would restrict the per call rate to a lower limit, such as 768 kbps, then that restricted rate of 768 kbps will take precedence over the Default Call Bandwidth rate.

There are also two settings that are used to down speed calls that are somewhat self-explanatory; Downspeed per call mode and Downspeed total mode. The per call mode pertains to each individual call attempt, and total mode refers to all calls occurring concurrently. Downspeed mode has two configuration settings, On or Off, with the default being On. Now let’s apply these default settings to the last call scenario we were examining where endpoint 4001 calls endpoint 4002 at 2 Mbps. Obviously, this call attempt cannot continue at this bandwidth rate because the per call bandwidth limit within the Default Subzone is 768 kbps, which is the rate to which this call would down speed.

Now let’s imagine another call scenario that assumes the down speed setting is on. If endpoint 5001 calls endpoint 6001 at 2 Mbps, the call would down speed. However, there are several aspects to this topology that must be considered. First, the two endpoints involved with this call attempt are registered to different Subzones. Endpoint 5001 is registered to Subzone 1 and endpoint 6001 is registered to Subzone 2. So, when examining the bandwidth limitations, the In and Out limit is the one to examine the closest. Second, these two subzones are not connected together with a direct link. Each Subzone is connected to the Default Subzone, so the bandwidth limitations of the Default Subzone must also be considered when examining the limitations of this call attempt. The In and Out limitations from the source endpoint towards the destination endpoint are 384 kbps for Subzone 1, 512 kbps for Default Subzone and 512 kbps for Subzone 2. The lowest restrictive rate for bandwidth is 384 kbps, so that is the rate to which the call will down speed.

One final call scenario to consider with Subzone bandwidth limitations pertains to call behavior when the total bandwidth limitation is exceeded. First imagine endpoint 4001 calls endpoint 4002 at 768 kbps. The call would go through as dialed because both endpoints are registered to the same subzone and the bandwidth limitation for calls within that subzone is 768 kbps. Now imagine, with that call still connected, endpoint 5002 calls endpoint 6002 at 384 kbps. As stated in the previous call scenario, the In and Out limitations from the source endpoint towards the destination endpoint are 384 kbps for Subzone 1, 512 kbps for Default Subzone and 512 kbps for Subzone 2. So on the surface it would seem that this call would proceed without needing to down speed. However, the Total call bandwidth in the Default Subzone is 1024 kbps, and there is already a call up at 768 kbps. If you subtract 1024 by 768 you come up with 256 kbps. Therefore, the call attempt from 5002 to 6002 would down speed to 256 kbps even though neither endpoint involved with the call are registered to the Default Subzone.

Subzone bandwidth settings are configured in the Subzones themselves, and Subzones are configured in the Local Zone. Therefore, it is easy to remember what menu to use to configure Subzone bandwidth settings. In the Expressway web interface navigate to Configuration > Local Zone and then either select the Default Subzone, Traversal Subzone, or Subzone menu, depending on which Subzone you want to configure. Remember that the Traversal Subzone will only show two menu options for configuring bandwidth restrictions, because endpoints cannot register to this Subzone. Alternatively, the Default Subzone, or other subsequent Subzones you may have created, will possess three menu options for configuring bandwidth restrictions. Figure 8-4 illustrates the bandwidth configuration menus on both the Default Subzone and Traversal Subzone.

Images

Figure 8-4 Bandwidth Restriction Menus using Subzones

Links and Pipes Bandwidth Management

As mentioned in the previous section, there is another bandwidth restriction method in the Cisco Expressway called Pipes that can be used in conjunction with or as an alternative to the Subzone bandwidth restriction method. A Pipe is a bandwidth restriction that is applied to Links. Remember that Links have no bandwidth restriction capability in and of themselves. Links are simply logical connections between two Subzones, or between a Subzone and a Zone. However, a Link can have zero, one, or two pipes applied to it. Additionally, a single pipe can be applied to more than one link – in which case that total bandwidth limit is the single total for calls across all links that Pipe is applied to. I will explain this more in a moment.

First, I want to answer the question, why use Pipes with Subzones? When the VCS was created there were always endpoints registered to it. Therefore, subzones were used to group endpoints together so that they could be managed the same way, such as with bandwidth restrictions. Some of these endpoints were even soft clients, so they were not always central to one location, and didn’t have a set bandwidth rate applied to them. This created a need to control them more restrictively than endpoints that live in a single location. Additionally, there were bandwidth restrictions that needed to control calls outside the local zone, such as neighboring VCSs. This is where Pipes comes into the picture. Zones do not have a bandwidth restriction setting like Subzones do. Therefore, a Pipe can be applied to the Link connected to the Zone, and all calls out that Zone will be restricted by the bandwidth rates defined within that Pipe.

With all that stated, let’s examine scenarios when Pipes are used instead of Subzones. When Cisco first introduced the Expressway series no endpoints could register directly to the Expressway Core or Edge. Therefore, Subzones and the bandwidth restrictions they contain were not needed on these servers. However, Pipes did still exist and were commonly used to control bandwidth. Even though the Expressways can now support direct registration, in many deployments they still only serve to proxy the registration requests to the CUCM. If this is how the Expressways are used within your production environment, then Subzone bandwidth management is not needed. Pipes would be the only logical mechanism to use for controlling bandwidth from within the Expressway.

You should now have a better understanding of when to use Pipes, so let’s examine the characteristics of Pipes. Since Links are defined as logical connections between two Subzones or between a Subzone and a Zone, and Pipes are applied to Links, Pipes can be defined as bandwidth limitations between two Subzones or between a Subzone and a Zone. They restrict bandwidth over a link in order to model any physical network limitations. Pipe bandwidth restrictions can be configured “per call” and “total bandwidth” between endpoints, just as they are configured in the Traversal Subzone. Pipes can be applied to one or more links. Consider the following scenarios where Pipes can be used:

Images When calls are placed between endpoints in different Subzones, it is possible to control the bandwidth used on the link between them.

Images After creating a Pipe it must be assigned to a link. Calls traversing the link will take the pipe’s bandwidth allocation into consideration.

Images Pipes may be shared between one or more links. This configuration is used to model the situation where a site communicates with several other sites over the same broadband connection to the Internet. Each link may have up to two pipes that are associated with it. This setup is useful for modeling two sites, each with their own broadband connection to the Internet backbone.

Images A single call can be limited by bandwidth restrictions within Subzones and any pipes at the same time if these restrictions are within the path of the call.

One Pipe, One Link:

Images Applying a single pipe to a single link is useful when you wish to apply specific limits to calls between a subzone and another specific subzone or zone. When a pipe is applied to a link, it will restrict the bandwidth of calls that are made between the two nodes of the link. These restrictions will apply to calls in either direction. Normally a single pipe would be applied to a single link. However, one or more pipes may be applied to one or more links, depending on how you wish to model your network.

Images

One Pipe, Two or More Links

Images As illustrated in the previous figure, one Pipe can be applied to more than one link. Notice in the figure that there are two distinct Links; one connecting the Default Subzone to Subzone 1 and another connecting the Default Subzone to Subzone 2. However, the Pipe applied to both links is called Pipe 1. Since this is the same pipe, the bandwidth limits will apply the same on both links. If calls between endpoints in the Default Subzone and Subzone 1 consume all the total bandwidth within Pipe 1, then no calls are possible between endpoints in Subzone 2 to any other subzone.

Images Each pipe may be applied to multiple links. There is no limit to the number of links to which a Pipe can be applied.

Images This solution is used to model the situation where one site communicates with several other sites across a Wide Area Network (WAN) connection.

Images A pipe should be configured to represent the WAN connection, and then applied to all the links.

Images This solution will allow you to configure the bandwidth options for calls in and out of that site.

Figure 8-5 illustrates the first two applications of Pipes within the Cisco Expressway.

Images

Figure 8-5 Pipes Applied to One or More Links

Images

Two Pipes, One Link:

Images Each link may have up to two pipes that are associated with it.

Images This scenario is used to model the situation where two nodes of a link use different connection rates across the WAN.

Images Each location should then have its own pipe limitations based on its own connection rates, resulting in the link between the two nodes being subject to the bandwidth restrictions of both pipes.

This third application of Pipes on the Cisco Expressway can be illustrated in Figure 8-6.

Images

Figure 8-6 Two Pipes Applied to One Link

In Figure 8-6 there is a single Expressway being used to span three different office locations across a WAN. The Default Subzone represents the Headquarter office, Subzone 1 represents Branch Office 1, and Subzone 2 represents Branch Office 2. Each office has a different connection rate across the WAN, therefore bandwidth restrictions need to be instituted for each site based on these bandwidth restrictions. The network is a shared network, meaning both video, and data share the same network. So, when creating pipes for each office location only half the available bandwidth will be allocated to video. This will leave plenty of bandwidth available for day-to-day operations and important business tasks, such as updating Facebook or Tweeting what you had for lunch. No office can function in today’s market without these capabilities. Again, I am using smaller numbers than you would normally use in a production environment for easier math calculations.

The HQ office has a 4 Mbps connection available to the WAN. If I half the network connection rate and allocate that to the total bandwidth limit, it will be 2048 kbps. Per call will be 384 kbps for all office locations. I can create Pipes all day long and they will do no good unless they are applied to Links. Since the Default Subzone represents the HQ office, and Pipe 1 represents the bandwidth limitations of the HQ office, Pipe 1 needs to be applied to all links that connect with the Default Subzone.

Branch office 1 has a network connection of 2 Mbps. By halving that network connection rate and allocating it to the total bandwidth limit, Pipe 2 will have 1024 kbps of total bandwidth available. Again, the per call limit will be set to 384 kbps. Since Branch Office 1 is represented by Subzone 1 and Pipe 2 represents the bandwidth limitations of Branch Office 1, Pipe 1 needs to be applied to all the links that connect with Subzone 1. If you can examine Figure 8-6 and ignore all the Pipes except the ones I have mentioned up till now, you should notice that the link between the Default Subzone and Subzone 1 will now have two Links applied to it.

Finally, Branch office 2 has a network connection of 1 Mbps. By halving that network connection rate and allocating it to the total bandwidth limit, Pipe 3 will have 512 kbps of total bandwidth available. Again, the per call limit will be set to 384 kbps. Since Branch Office 2 is represented by Subzone 2 and Pipe 3 represents the bandwidth limitations of Branch Office 2, Pipe 3 needs to be applied to all the links that connect with Subzone 2. Now all the Pipes represented in Figure 8-6 have been explained. Each Link in this scenario will have two Pipes applied to them.

If Endpoint 4001 calls endpoint 6001 at the highest bandwidth rate available, the call would connect at 384 kbps. This bandwidth cost will be subtracted from the totals of Pipe 1 and Pipe 3. If, while that call is still connected, endpoint 5001 calls endpoint 6002 at the highest bandwidth rate available then the call would only connect at 128 kbps. Because the first call at 384 kbps is subtracted from the 512 kbps total limit of Pipe 3, that only leaves 128 kbps. Even though the per call rate is set to 384 kbps, there is not enough bandwidth available to support that rate. So, the call will connect at 128 kbps and this bandwidth cost will be subtracted from Pipe 2 and Pipe 3. No one else can call into Subzone 2 until one of the connections ends, but endpoint in Subzone 1 and Default Subzone can still call each other since there is plenty of total bandwidth left in Pipe 1 and Pipe 2.

There are basically two main steps to configuring Pipes. You need to create the Pipe and then apply the Pipe to a Link.

Step 1. To create a Pipe, navigate to Configuration > Bandwidth > Pipes. Click New and configure the following settings:

Images Name: Provide a name for the pipe that describes its purpose.

Images Total bandwidth available

Bandwidth restriction: Select from the dropdown list; Unlimited, Limited or No bandwidth.

Total bandwidth limit (kbps): Enter a numeric value to represent the total bandwidth limit in kbps that is being allowed for all concurrent calls.

Images Calls through this pipe (This is the per call bandwidth limitation.)

Bandwidth restriction: Select from the dropdown list; Unlimited, Limited or No bandwidth.

Per call bandwidth limit (kbps): Enter a numeric value to represent the per calll bandwidth limit in kbps that is being allowed for all concurrent calls.

Step 2. Click Create Pipe when finished. Figure 8-7 illustrates the Pipe configuration menus.

Images

Figure 8-7 Creating Pipes on the Cisco Expressway

Step 3. To apply the Pipe to a Link, navigate to Configuration > Bandwidth > Links. (You can also click the View, edit add, and delete links hyperlink at the bottom of the Pipes page under the Related tasks section.)

Step 4. Either click on the Link name or click on the View/Edit action. Do not click on the Node 1 or Node 2 name. That will redirect you to that Subzone or Zone.

Step 5. Under the Pipe 1 or Pipe 2 field, use the dropdown menu to select the Pipe(s) that should be applied to this link. The order does not matter if selecting more than one Pipe. If only selecting one Pipe, it does not matter which Pipe entry you enter it in either.

Step 6. Click Save once finished. Your bandwidth settings are now set. Figure 8-8 illustrates how to apply Pipes to Links on the Cisco Expressway.

Images

Figure 8-8 Applying Pipes to Links on the Cisco Expressway

Call Control Using Pipes

The primary purpose of Pipes is to limit bandwidth for calls that pass through the Cisco Expressway. Since Pipes are applied to links, they can also be used for call control. Before I explain how they can be used in this capacity, it is important to first review a fundamental behavior of call routing within the Cisco Expressway. When calls are routed between Subzones or between a Subzone and Zone, call will always take the shortest path. If that path is blocked, then the call will not re-route across another logical path. The call will simply fail. Figure 8-9 illustrates a scenario that exemplifies this behavior of call control using Pipes.

Images

Figure 8-9 Using Pipes for Call Control

Imagine a company that uses the Expressway for endpoint registration. Sales associates need endpoints so that they can communicate with customers and generate sales for the company. The accounting team also need endpoints so that they can communicate with the sales team about expense reports and account receivables. The sales team will often use the Cisco Meeting Server for conferences with customers and vendors, however, the accounting team does not need these services, so their access to the Cisco Meeting Server should be restricted to ensure the resources are available to the sales team when they need them.

In order to create this environment within the Cisco Expressway, the Sales endpoints are setup to register to the Default Subzone, and the accounting endpoints are setup to register to Subzone 1. The Cisco Meeting Server does not register to the Expressway. Therefore, a Neighbor Zone needs to be created that points to the Cisco Meeting Server. An extra link also needs to be created between Subzone 1 and the Neighbor Zone. Now the magical piece to this whole solution can be applied. A Pipe needs to be created with a total bandwidth setting of No Bandwidth and applied to the link that was just created between Subzone 1 and the Neighbor Zone.

Since there are no restrictions between the Default Subzone and the shortest path to the Neighbor Zone the Sales team will still be able to call out to the Cisco Meeting Server. Since there are no restrictions between the Default Subzone and the shortest path to Subzone 1 the Sales team will still be able to call out to the accounting team and vice versa. However, since Subzone 1 is restricted with No Bandwith along the shortest path to the Neighbor Zone, any call attempts in that direction will fail.

Now let’s change this scenario so you can see why it is important to set this solution up the way that has previously been described. Assume for a moment that the link between Subzone 1 and the Neighbor Zone was never created. Now the shortest path from Subzone 1 to the Neighbor Zone is through the Default Subzone. If I apply the No Bandwidth Pipe to the link connecting these two Subzones then the Accounting endpoints and the Sales endpoints cannot communicate with one-another, which is not the desired outcome. If the No Bandwidth Pipe is applied to the Link between the Default Subzone and the Neighbor Zone then Sales and Accounting can communicate with one-another, but Sales will not be able to access the Cisco Meeting Server. Therefore, in order to use Pipes as a call control mechanism, such as has been described with this scenario, a “shortest path” must be created between Subzone 1 and the Neighbor Zone, then the No Bandwidth Pipe needs to be applied to that link.

Exam Preparation Tasks

As mentioned in the section “How to Use This Book” in the Introduction, you have a couple of choices for exam preparation: the exercises here, Chapter 22, “Final Preparation,” and the exam simulation questions in the Pearson Test Prep Software Online.

Review All Key Topics

Review the most important topics in this chapter, noted with the Key Topics icon in the outer margin of the page. Table 8-2 lists a reference of these key topics and the page numbers on which each is found.

Images

Table 8-2 Key Topics for Chapter 8

Images

Complete Tables and Lists from Memory

There are no Memory Lists or Tables in this chapter.

Define Key Terms

Define the following key terms from this chapter and check your answers in the glossary:

Bandwidth

Default Call Bandwidth

Downspeed Mode

Downspeed Per Call

Downspeed Total

Pipe

Wide Area Network (WAN)

Q&A

The answers to these questions appear in Appendix A. For more practice with exam format questions, use the Pearson Test Prep Software Online.

1. What are the three bandwidth limitation modes?

2. List three ways Pipes can be applied to links.

Answers

1. What are the three bandwidth limitation modes?

a. None

b. Limited

c. Unlimited

2. List three ways Pipes can be applied to links.

a. One Pipe, one Link

b. One Pipe, two or more Links

c. Two Pipes, one Link

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