We talked about the main Cisco Stacking switches before. The main Stacking technology includes FlexStack, FlexStack Plus, StackWise, StackWise Plus, StackWise-160, StackWise-480 and Virtual Switching System (VSS). In this article, we will discuss the StackWise-480. What’s the StackWise-480?The new StackWise-480 architecture builds high-speed, 480 Gbps per stack switch member in the stack ring. This speed is much higher than the traditional StackWise Plus design in the Catalyst 3750X Series platform.
The Stackwise 480 supports a centralized control-plane process, 1+1 state full redundancy achieved by SSO, Distributed L2/L3 forwarding redundancy, and utilizes the IOS HA framework.
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The new Stackwise 480 cables are vastly different to the old clunk silver battleships. The streamed lined cable pictured above replaces the old style. Its makeup utilizes the concept of rings. There are three east bound and three west bound rings. Each ring consists of 40 gigabit bandwidth. Amounts to 240 gigabit through the stack. With reuse this number climbs to 480 gigabit. Packets traversing the stack-ring are segmented and reassembled in hardware. This is done at 256 byte segments.
A fault in the stack is detected initially in hardware. This detection is passed into the software. Once the software is notified the Ring Wrap process is initiated. This process is sub millisecond. The process to heal is similar. The switches on either side of the failure use their hardware first to detect the other side. The software validates the link and the connection is reestablished gracefully. This process is known as the Ring unwrap. It is important to note that the unwrap is slower than the wrap.
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Unicast packets on a Stackwise 480 support destination stripping. This means that when a packet reaches its destination is removed from the ring. This leaves the rest of the rings bandwidth free to be used. Multicast packets rely on source stripping. Source stripping requires a packet that traverse the ring upon arrival to the destination, copy the packet and send it the rest of the way to the source and then is removed from the ring. This is wasteful and bandwidth intensive.
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Unicast packets on a stack work on a token based access scheme with six different tokens associated to the six rings. Depending on the tokens which each specific ASIC has access to they might use two or three, or consume all six. Due to the nature of 3 east and 3 west links the ability to pass traffic around half the ring is extremely effective. I like to remember the behavior of Unicast packets on a stack as half-ring!
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Multicast packets on a Stackwise 480 works with source stripping. When a multicast packet comes in they are sent out to particular ASICs. It is sent out around the ring and interested parties pick up the packet. It is continued around the stack and back to the source where it is stripped and discarded. This method allows stack members and their ASICs that might need the multicast packet to be able to get it. Any node that does get the multicast packet replicates it for the outbound and local ports. This saves on congestion arising from sending individual copies.
The 3850 Stackwise 480 expands upon the new inbuilt ASICs to help achieve up to 200 forwarding, non blocking ports. Stackwise 480 allows the entire unit to stack up to 480 Gigabits of forwarding capacity. There is a limit of 4 switches per stack and this is something to consider during a design. The notion of an Master, hot-standby, and standby units allows the switch to be highly resilient due to the ability to now leverage SSO technologies.
The ASIC aforementioned which is the beating heart of the 3850 is known as the UADP ASIC. It supports programmability and intelligence with foundation support for Cisco Open Network Environment, Software Defined Unicorn support, and OnePK movements. This is expected to be expanded via software updates.
Reference From https://networkinferno.net/cisco-3850-stackwise
Scalable StackWise-480 Architecture on Cisco 3850 Series Switches
Catalyst 3850 Series Switches are supported in three different form factor models: 48 ports 10/100/1000, 24 ports 10/100/1000, and 12/24 Ethernet small form-factor pluggable (SFP) ports. The hardware design of each model is cost-effective to support different network capacity load and switching performance. For consistent converged access capabilities with rich Unified Access network services in the wiring closet, the software parity remains common in Catalyst 3850 switch models.
The Cisco IOS XE 3.3 software release brings parity of the nine-members-switch-stack capability that can be physically connected in a ring to form a single, unified, virtual stack system. Depending on the port density requirement in each stack switch, the Catalyst 3850 hardware provides flexibility for mix-mode support between 48‑, 24-, and 12-port systems in single stack ring.The Catalyst 3850 deployed in stack mode is designed to deliver deterministic and non-blocking switching performance for up to 468 ports, including wired and wireless network devices. The switching performance delivers hardware-accelerated, integrated borderless network services such Power over Ethernet (PoE) and PoE Plus, quality of service (QoS), access control lists (ACLs), Flexible Netflow, and many more services on every port.
StackWise-480 supports a mixed stack of any Catalyst 3850 models (48 ports 10/100/1000, 24 ports 10/100/1000, and 12/24 Ethernet SFP ports). You can mix the switches with different number of access ports (48, 24, and 12), different type of access ports (copper and fiber, PoE, and non-PoE-capable), and different network modules. But all switches in one stack must have the same version of IOS XE and the same feature set license. A mixed stack of LAN base switches with IP base or IP services is not supported. Catalyst 3850 Series Switches with a LAN base feature set can only stack with other Catalyst 3850 Series LAN base switches. The same applies to IP base and IP services as well.
Cisco StackWise Architecture Comparison
More info http://www.cisco.com/c/en/us/products/collateral/switches/catalyst-3850-series-switches/white-paper-c11-734429.html
Cisco Catalyst 3850: Comparison with Catalyst 3750-X
*Available only for the 48-port RJ45 models and for the 12-port (or higher) 10 Gigabit capable models
**StackWise-480 and StackPower not supported on the 48-port 10G SFP+ switch
*** Supported on the 24-port and 48-port Multigigabit Switch and also on the 24-port 10G SFP+ switch
****Optional uplink modules are not supported on the 48-port 10G SFP+ switch
More Related Cisco Switch Stack Topics
All about Cisco’s Stacking Switches
Cisco Switch Stacking Using a Couple of Cisco Catalyst 3650
Cisco 2960-S Series Stacking
Stacking Cisco 3750 Switches Benefits & Stacking Rules
How to Stack Cisco 2960S Switches…Detailed Examples Here
Cisco Catalyst 3850 switch Stacking
Cisco Catalyst 2960-S & 2960-X Mixed Stacking
The Stackwise 480 supports a centralized control-plane process, 1+1 state full redundancy achieved by SSO, Distributed L2/L3 forwarding redundancy, and utilizes the IOS HA framework.
The new Stackwise 480 cables are vastly different to the old clunk silver battleships. The streamed lined cable pictured above replaces the old style. Its makeup utilizes the concept of rings. There are three east bound and three west bound rings. Each ring consists of 40 gigabit bandwidth. Amounts to 240 gigabit through the stack. With reuse this number climbs to 480 gigabit. Packets traversing the stack-ring are segmented and reassembled in hardware. This is done at 256 byte segments.
A fault in the stack is detected initially in hardware. This detection is passed into the software. Once the software is notified the Ring Wrap process is initiated. This process is sub millisecond. The process to heal is similar. The switches on either side of the failure use their hardware first to detect the other side. The software validates the link and the connection is reestablished gracefully. This process is known as the Ring unwrap. It is important to note that the unwrap is slower than the wrap.
Unicast packets on a Stackwise 480 support destination stripping. This means that when a packet reaches its destination is removed from the ring. This leaves the rest of the rings bandwidth free to be used. Multicast packets rely on source stripping. Source stripping requires a packet that traverse the ring upon arrival to the destination, copy the packet and send it the rest of the way to the source and then is removed from the ring. This is wasteful and bandwidth intensive.
Unicast packets on a stack work on a token based access scheme with six different tokens associated to the six rings. Depending on the tokens which each specific ASIC has access to they might use two or three, or consume all six. Due to the nature of 3 east and 3 west links the ability to pass traffic around half the ring is extremely effective. I like to remember the behavior of Unicast packets on a stack as half-ring!
Multicast packets on a Stackwise 480 works with source stripping. When a multicast packet comes in they are sent out to particular ASICs. It is sent out around the ring and interested parties pick up the packet. It is continued around the stack and back to the source where it is stripped and discarded. This method allows stack members and their ASICs that might need the multicast packet to be able to get it. Any node that does get the multicast packet replicates it for the outbound and local ports. This saves on congestion arising from sending individual copies.
The 3850 Stackwise 480 expands upon the new inbuilt ASICs to help achieve up to 200 forwarding, non blocking ports. Stackwise 480 allows the entire unit to stack up to 480 Gigabits of forwarding capacity. There is a limit of 4 switches per stack and this is something to consider during a design. The notion of an Master, hot-standby, and standby units allows the switch to be highly resilient due to the ability to now leverage SSO technologies.
The ASIC aforementioned which is the beating heart of the 3850 is known as the UADP ASIC. It supports programmability and intelligence with foundation support for Cisco Open Network Environment, Software Defined Unicorn support, and OnePK movements. This is expected to be expanded via software updates.
Reference From https://networkinferno.net/cisco-3850-stackwise
Scalable StackWise-480 Architecture on Cisco 3850 Series Switches
Catalyst 3850 Series Switches are supported in three different form factor models: 48 ports 10/100/1000, 24 ports 10/100/1000, and 12/24 Ethernet small form-factor pluggable (SFP) ports. The hardware design of each model is cost-effective to support different network capacity load and switching performance. For consistent converged access capabilities with rich Unified Access network services in the wiring closet, the software parity remains common in Catalyst 3850 switch models.
The Cisco IOS XE 3.3 software release brings parity of the nine-members-switch-stack capability that can be physically connected in a ring to form a single, unified, virtual stack system. Depending on the port density requirement in each stack switch, the Catalyst 3850 hardware provides flexibility for mix-mode support between 48‑, 24-, and 12-port systems in single stack ring.The Catalyst 3850 deployed in stack mode is designed to deliver deterministic and non-blocking switching performance for up to 468 ports, including wired and wireless network devices. The switching performance delivers hardware-accelerated, integrated borderless network services such Power over Ethernet (PoE) and PoE Plus, quality of service (QoS), access control lists (ACLs), Flexible Netflow, and many more services on every port.
StackWise-480 supports a mixed stack of any Catalyst 3850 models (48 ports 10/100/1000, 24 ports 10/100/1000, and 12/24 Ethernet SFP ports). You can mix the switches with different number of access ports (48, 24, and 12), different type of access ports (copper and fiber, PoE, and non-PoE-capable), and different network modules. But all switches in one stack must have the same version of IOS XE and the same feature set license. A mixed stack of LAN base switches with IP base or IP services is not supported. Catalyst 3850 Series Switches with a LAN base feature set can only stack with other Catalyst 3850 Series LAN base switches. The same applies to IP base and IP services as well.
Cisco StackWise Architecture Comparison
| Catalyst 3850 StackWise-480 | Catalyst 3650 StackWise-160 | Catalyst 3750-X StackWise Plus | |
| Stack ports per switch | 2 | 2 | 2 |
| Ring per stack port | 6 | 2 | 2 |
| Throughput per ring (bi-directional) | 40 Gbps | 40 Gbps | 16 Gbps |
| Throughput per stack port/ASIC | 240 Gbps | 80 Gbps | 32 Gbps |
| Throughput per switch (dual stack ports) with SRP | 480 Gbps | 160 Gbps | 64 Gbps |
More info http://www.cisco.com/c/en/us/products/collateral/switches/catalyst-3850-series-switches/white-paper-c11-734429.html
Cisco Catalyst 3850: Comparison with Catalyst 3750-X
| Features | Cisco Catalyst 3750-X | Cisco Catalyst 3850 |
| Stacking bandwidth | 64 Gbps | 480 Gbps** |
| Cisco IOS Software wireless controller | No | Yes |
| Queues per port | 4 | 8 |
| Quality-of-service (QoS) model | MLS | MQC |
| Uplinks**** | 4 x 1GE 2 x 10GE NM 4 x 1 GE or 2 x 10GE SM | 4 x 1GE 2 x 1/10GE 4 x 1/10GE* 8 x 10GE*** 2 x 40GE*** |
| Downlinks | 24 or 48 RJ45 interfaces 12 or 24 SFP receptacles | 24 or 48 RJ45 interfaces 12 or 24 SFP receptacles 12, 24, or 24 SFP+ receptacles |
| StackPower | Yes | Yes** |
| Flexible NetFlow support | Yes (C3KX-SM-10G required) | Yes |
| Multicore CPU for hosted services | No | Yes |
| Flash size | 64 Mb | 2 Gb |
| Operating system | Cisco IOS Software | Cisco IOS XE Software |
**StackWise-480 and StackPower not supported on the 48-port 10G SFP+ switch
*** Supported on the 24-port and 48-port Multigigabit Switch and also on the 24-port 10G SFP+ switch
****Optional uplink modules are not supported on the 48-port 10G SFP+ switch
More Related Cisco Switch Stack Topics
All about Cisco’s Stacking Switches
Cisco Switch Stacking Using a Couple of Cisco Catalyst 3650
Cisco 2960-S Series Stacking
Stacking Cisco 3750 Switches Benefits & Stacking Rules
How to Stack Cisco 2960S Switches…Detailed Examples Here
Cisco Catalyst 3850 switch Stacking
Cisco Catalyst 2960-S & 2960-X Mixed Stacking