Karteikarten
Chapter 10: Aggregating Switch Links
Karten in diesem Stapel (36)
- 1What is the throughput of FastEthernet, GigaEthernet and 10-GigaEthernet?• FastEthernet: 200 Mbps
• GigaEthernet: 2 Gbps
• 10-GigaEthernet: 20 Gbps - 2How can act a EtherChannel? as a access or trunk link?Can act either as access or trunk logical link.
- 3By which name is known all the bundled physical links of the logical EtherChannel interface in a switch?As a Port Channel
- 4What is the delay when a link of the bundle fails?Failover occurs in less than a few milliseconds and is transparent to the end user. Likewise, as links are restored, the load automatically is redistributed among the active links.
- 5What happen if a switch fails?For this situation exist a more robust one as distributting the physical links across multiple switches at the end of the EtherChannel. Configuring a switch as logical or virtual switch such as the Cisco stackable Catalyst switches or chassis based Virtual Switching System (VSS) switch families.
- 6multichassis EtherChannel (MEC)Links connected to the first switch in a stack and links connected to the second switch in a stack.
- 7How is distributed the traffic in an Etherchannel?Frames are forwarded on a specific Link as a result of a hashing algorithm.
- 8What elements are used for the calculation of the hash's algorithm?This algorithm use:
• SRC IP add, DST Ip address or a combination of both
• SRC and DST MAC address
• TCP/UDP numbers - 9How is used this algorithm?The hash algorithm computes a binary pattern that selects a link number in the
bundle to carry each frame. - 10What happen if one pair of hosts has a much greater volume of traffic than the other pair?This still can create a load imbalance. To remedy this condition, you should consider other methods of hashing algorithms for the channel.
For example, a method that combines the source and destination addresses along with UDP or TCP port numbers in a single XOR operation can distribute traffic much differently. - 11Configuring EtherChannel Load BalancingSwitch(config)# port-channel load-balance method
Configure frame distribution for all EtherChannel switch links - 12Types of EtherChannel Load-Balancing Methods• src-(ip, mac, port): Bits
• dst-(ip, mac, port): Bits
• src-dst-(ip, mac, port): XOR
**Only hash operation with ports are available in 4500, 6500 switch models - 13What are the default configuration on switch?It depends from the model of switch, for example in 3750-X switch, the default is SRC-MAC.
- 14With which command we can verify the load-balancing method currently in use?Switch# show etherchannel load-balance
EtherChannel Load-Balancing Configuration:
src-mac - 15But if IP load balancing is being used, what happens to non-IP frames?If a frame cannot meet the load-balancing criteria, the switch automatically falls back to the “next lowest” method. With Ethernet, MAC addresses must always be present, so the switch distributes those frames according to their MAC addresses.
- 16What we have to consider when choose the load-balancing method?Consider the type of addressing that is
being used on the network. If most of the traffic is IP, it might make sense to load balance according to IP addresses or TCP/UDP port numbers. - 17EtherChannel Negotiation Protocols
- 18What are the condition to form a EC with PAgP?Ports that have the same
• neighbor device ID
• port group capability
Are bundled together as a bidirectional, point-to-point EtherChannel link. - 19PAgP form EC with static VLANs or trunking?On ports that are configured for either identical static VLANs or trunking
- 20What happen if a modify an PortChannel config?Dynamically modifies parameters of the EtherChannel if one of the bundled ports is modified. PAgP reconfigures that
parameter for all ports in the bundle. - 21What are the mods of PAgP?Active mode (desirable), in which a switch actively asks a far end switch to negotiate an EtherChannel, or in passive mode (auto, the default), in which a switch negotiates an EtherChannel only if the far end initiates it.
- 22What is the standard of LACP?LACP is a standards-based alternative to PAgP, defined in IEEE 802.3ad
- 23What are the differences with PAgP in neighbor's terms?LACP also assigns roles to the EtherChannel’s endpoints. The switch with the lowest system priority (a 2-byte priority value followed by a 6-byte
switch MAC address) is allowed to make decisions about what ports actively are participating in the EtherChannel at a given time. - 24How is defined the priority basis on LACP?A low value indicates a higher priority. We can set of up to 16 potential links can be defined for each EtherChannel. Through LACP, a switch selects up to eight of these having the lowest port priorities as active EtherChannel links at any given time. The other links are placed in a standby state
- 25What are the LACP modes?Active mode (active), in which a switch actively asks a far-end switch to negotiate an EtherChannel, or in passive mode (passive), in which a switch negotiates an EtherChannel only if the far end initiates it.
- 26Configuring a PAgP EtherChannelSW(config)# interface G0/0
SW(config-if)# channel-protocol pagp
SW(config-if)# channel-group "1 to 64" mode { on | {{ auto | desirable }
[ non-silent ]}} - 27What is the silent submode?By default, PAgP operates in silent submode with desirable or auto modes. and allows ports to be added to an EtherChannel EVEN IF the other end of the link is silent and never transmits PAgP packets.
- 28How works the silent submode?The silent submode listens for any
PAgP packets from the far end, looking to negotiate a channel. If none is received, silent submode assumes that a channel should be built anyway, so no more PAgP packets are expected from the far end. - 29When is the silent submode useful?When at the other end we have a FileServer or a Network Analyser that doesn't participate in PAgP.
- 30What if we have a PAgP capable switch at the far end?You should add the NON-SILENT
keyword to the desirable or auto mode, to requires each port to receive PAgP packets before adding them to a channel. - 31example of PAgP configurationSW(config)# port-channel load-balance src-dst-port
SW(config)# interface range gig 1/0/1 – 4
SW(config-if)# channel-protocol pagp
SW(config-if)# channel-group 1 mode desirable non-silent - 32Configuring a LACP EtherChannelSW(config)#lacp system-priority "priority"
SW(config)#interface G0/0/2
SW(config-if)#channel-protocol lacp
SW(config-if)#channel-group "1 to 64" mode { on | passive | active }
SW(config-if)#lacp port-priority "priority" - 33LACP system priority1 to 65,535; default 32,768
If desired, one switch should be assigned a lower system priority than the other
so that it can make decisions about the EtherChannel’s makeup. Otherwise, both switches will have the same system priority (32,768), and the one with the lower MAC address will become the decision maker. - 34LACP system priority valuesDefault: 32768 + Lower MAC address
- 35Number of interfaces in PortChannelWe can set up to 16 interfaces where only 8 will be in the ACTIVE mode and the 8 remaining will be in STANDBY mode in case of failure.
- 36Standby LACP interfacesUse the "lacp port-priority" command to set the priority desired (1 to 65.535; default 32.768). A lower value will be elected as ACTIVE and a higher value will be STANDBY. If we use the default behavior the lower port numbers (in interface number order) are used to select ACTIVE ports.
Informationen
- Beschreibung
- 300-115 CCNP SWITCH 300-115 (Part III: Working with Redundant Links) Karteikarten am Chapter 10: Aggregating Switch Links, erstellt von Luis Domínguez am 07/05/2018.
- Erstellt von
- Luis Domínguez
- Aufrufe
- 0
- Bewertung
Mehr zu EtherChannel and Link Aggregation