Скачать с ютуб Routed Access Hardware Companion - Cisco Catalyst Modular Configuration Switches (Chassis) в хорошем качестве

Routed Access Hardware Companion - Cisco Catalyst Modular Configuration Switches (Chassis)

To download the campus design guide, click here: http://www.vology.com/cisco/design-gu... Today we’re talking about the best Catalyst modular switches for the Routed Access topology. We recommend modular switches for ease of management, simplicity and when high availability is a top requirement in the deployment. When it comes to Catalyst modular switches, the potential combinations of chassis, supervisor, line card and power supplies can be a little overwhelming. Assuming a 10 Gigabit backbone, here’s our list of requirements: IP Base feature set, Two 10 Gigabit uplinks, 15.4 watts of Power over Ethernet, 10/100/1000 Access Ports Today, there are three options for the Catalyst modular switches: Catalyst 6800 Right off the bat we can exclude Cisco’s latest 68xx modular switches. Yes, they are “cool” but they are WAY over the top when we consider our needs in a campus access switch. Catalyst 6500 The 6500 is a proven workhorse but really more suited to the Core, Distribution or Data Center access deployments. These deployments have different feature requirements like distribution forwarding. This brings the focus to the Catalyst 4500 which is specifically designed for the campus access wiring closet. Let’s take a deeper look. The first thing I would like to cover is the supervisor uplinks. Assuming that we are plugging into a 10 Gbps backbone, two 10 Gbps uplinks are all we need. With load balancing, this provides around a 12:1 oversubscription ratio and is well within design best practices for the 3, 6 and 7 slot chassis, for the campus access. Remember, this isn’t the server farm or data center where traffic loads and patterns are much different. Traffic in the campus access is sporadic. For the 10 slot chassis, two 10 Gbps uplinks would result in a 16:1 oversubscription ratio. Where the four 10 Gbps uplinks on the supervisor 8E would reduce the overscription ratios, this also adds quite a bit of cost to the solution. Next let’s look at the bandwidth available in each chassis slot. Depending on the supervisor, we have either 24 Gbps at a 2:1 oversubscription ratio or 48 Gbps with a 1:1 oversubscription ratio in the 7 slot chassis. Most would think that 1:1 is the natural choice but remember, we have a 12:1 oversubscription ratio in the uplinks, making the uplinks the bottleneck. So what is a 1:1 ratio in the each slot going to do for us? Nothing, it just adds cost. Note that only the 4507R chassis offers supervisor redundancy that protects against a single supervisor failure. The 4503-E and 4506-E chassis do not support redundant supervisors making this a single point of failure for the chassis. With the chassis and supervisor covered, let’s look at the line cards available for deployment. Looking at our requirements, we are only need 802.3f (15.4w) for Power over Ethernet and all of the cards meet this requirement. In fact all but one offer 802.3at (30w) or UPOE (60w) capabilities. 15.4 watts of Power over Ethernet will handle every IP Phone out there today and IP phones are getting more efficient, not less. So the “future proofing” that tends to be associated with the higher power standards just increases your cost. As you can see, some of these line cards support 48 Gbps and some 24 Gbps. As mentioned in the 4500 Chassis and Supervisor table, the real bottleneck is the uplinks on the supervisor. Meaning there is no advantage to the 48 Gbps capable lines cards, in this deployment. For a high availability chassis based access switch solution, we recommend the following build: 4507R chassis with two Supervisor 6L-E supervisors, five 4648-RJ45V-E line cards and two 6000 watt power supplies topped off with the IP Base feature set. This chassis based solution is simple and provides the highest availability for the wiring closet today. For scenarios where a redundant supervisor is not required, moving to single supervisor and a 4506-E or 4503-E chassis can offer quite a bit of savings. Where this configuration lacks the supervisor redundancy of the 4507R based solution, it does integrate the line cards allowing them to be managed as a single unit. To keep this in perspective, this solution would be considered comparable to a switch stack in terms of availability. But we’ll tackle that topic in our next video “Stackable vs Chassis” which promises to offer a little different perspective on this topic.