Download CCNP Cisco IP Switched Networks (SWITCH v2-0).braindumps.300-115.2019-02-10.1e.482q.vcex

The different etherchannel modes are described in the table below:

  

Both the auto and desirable PAgP modes allow interfaces to negotiate with partner interfaces to determine if they can form an EtherChannel based on criteria such as interface speed and, for Layer 2 EtherChannels, trunking state and VLAN numbers. 
Interfaces can form an EtherChannel when they are in different PAgP modes as long as the modes are compatible. For example:
  An interface in the desirable mode can form an EtherChannel with another interface that is in the desirable or auto mode.  
  An interface in the auto mode can form an EtherChannel with another interface in the desirable mode. 
An interface in the auto mode cannot form an EtherChannel with another interface that is also in the auto mode because neither interface starts PAgP negotiation.  
An interface in the on mode that is added to a port channel is forced to have the same characteristics as the already existing on mode interfaces in the channel. 
Reference: https://www.cisco.com/c/en/us/td/docs/switches/lan/catalyst4500/12-2/20ew/configuration/guide/config/channel.html

To start a new flow-based SPAN (FSPAN) session or flow-based RSPAN (FRSPAN) source or destination session, or to limit (filter) SPAN source traffic to specific VLANs, use the monitor session filter global configuration command. 
Usage Guidelines 
You can set a combined maximum of two local SPAN sessions and RSPAN source sessions. You can have a total of 66 SPAN and RSPAN sessions on a switch or switch stack. 
You can monitor traffic on a single VLAN or on a series or range of ports or VLANs. You select a series or range of VLANs by using the [ , | -] options. 
If you specify a series of VLANs, you must enter a space before and after the comma. If you specify a range of VLANs, you must enter a space before and after the hyphen ( -). 
VLAN filtering refers to analyzing network traffic on a selected set of VLANs on trunk source ports. By default, all VLANs are monitored on trunk source ports. You can use the monitor session session_number filter vlan vlan-id command to limit SPAN traffic on trunk source ports to only the specified VLANs. 
VLAN monitoring and VLAN filtering are mutually exclusive. If a VLAN is a source, VLAN filtering cannot be enabled. If VLAN filtering is configured, a VLAN cannot become a source. 
Reference: http://www.cisco.com/c/en/us/td/docs/switches/lan/catalyst3850/software/release/3se/network_management/command_reference/b_nm_3se_3850_cr/b_nm_3se_3850_cr_chapter_010.html#wp3875419997

You can analyze network traffic passing through ports or VLANs by using SPAN or RSPAN to send a copy of the traffic to another port on the switch or on another switch that has been connected to a network analyzer or other monitoring or security device. SPAN copies (or mirrors) traffic received or sent (or both) on source ports or source VLANs to a destination port for analysis. 
RSPAN supports source ports, source VLANs, and destination ports on different switches (or different switch stacks), enabling remote monitoring of multiple switches across your network. The traffic for each RSPAN session is carried over a user-specified RSPAN VLAN that is dedicated for that RSPAN session in all participating switches. The RSPAN traffic from the source ports or VLANs is copied into the RSPAN VLAN and forwarded over trunk ports carrying the RSPAN VLAN to a destination session monitoring the RSPAN VLAN. Each RSPAN source switch must have either ports or VLANs as RSPAN sources. The destination is always a physical port. 
Reference: http://www.cisco.com/c/en/us/td/docs/switches/lan/catalyst3750x_3560x/software/release/12-2_55_se/configuration/guide/3750xscg/swspan.html

If all of the routers are connected to each other using a layer 2 switch, then each router will only have the single switch port that it connects to as its neighbor. Even though multiple routing neighbors can be formed over a layer 2 network, only the physical port that it connects to will be seen as a CDP neighbor. CDP can be used to determine the physical topology, but not necessarily the logical topology.

The Link Layer Discovery Protocol (LLDP) is a vendor-neutral link layer protocol in the Internet Protocol Suite used by network devices for advertising their identity, capabilities, and neighbors on an IEEE 802 local area network, principally wired Ethernet. LLDP performs functions similar to several proprietary protocols, such as the Cisco Discovery Protocol (CDP). 
Reference: http://en.wikipedia.org/wiki/Link_Layer_Discovery_Protocol

VTP transparent switches do not participate in VTP. A VTP transparent switch does not advertise its VLAN configuration and does not synchronize its VLAN configuration based on received advertisements, but transparent switches do forward VTP advertisements that they receive out their trunk ports in VTP Version 2. 
Reference: http://www.cisco.com/en/US/tech/tk389/tk689/technologies_tech_note09186a0080094c52.shtml

VTP pruning increases network available bandwidth by restricting flooded traffic to those trunk links that the traffic must use to reach the destination devices. Without VTP pruning, a switch floods broadcast, multicast, and unknown unicast traffic across all trunk links within a VTP domain even though receiving switches might discard them. VTP pruning is disabled by default.  
VTP pruning blocks unneeded flooded traffic to VLANs on trunk ports that are included in the pruning-eligible list. The best explanation for why switch C is not seeing traffic from only some of the VLANs, is that VTP pruning has been configured.

RSTP works by adding an alternative port and a backup port compared to STP. These ports are allowed to immediately enter the forwarding state rather than passively wait for the network to converge. 
RSTP bridge port roles:
Root port – A forwarding port that is the closest to the root bridge in terms of path cost 
Designated port – A forwarding port for every LAN segment 
Alternate port – A best alternate path to the root bridge. This path is different than using the root port. The alternative port moves to the forwarding state if there is a failure on the designated port for the segment. 
Backup port – A backup/redundant path to a segment where another bridge port already connects. The backup port applies only when a single switch has two links to the same segment (collision domain). To have two links to the same collision domain, the switch must be attached to a hub. 
Disabled port – Not strictly part of STP, a network administrator can manually disable a port 
Reference: http://www.cisco.com/c/en/us/support/docs/lan-switching/spanning-tree-protocol/24062-146.html

RSTP can only achieve rapid transition to the forwarding state on edge ports and on point-to-point links, not on trunk links. The link type is automatically derived from the duplex mode of a port. A port that operates in full-duplex is assumed to be point-to-point, while a half-duplex port is considered as a shared port by default. This automatic link type setting can be overridden by explicit configuration. In switched networks today, most links operate in full-duplex mode and are treated as point-to-point links by RSTP. This makes them candidates for rapid transition to the forwarding state. 
Reference: http://www.cisco.com/c/en/us/support/docs/lan-switching/spanning-tree-protocol/24062-146.html

VTP pruning enhances network bandwidth use by reducing unnecessary flooded traffic, such as broadcast, multicast, unknown, and flooded unicast packets to only the switches that require it. VTP pruning increases available bandwidth by restricting flooded traffic to those trunk links that the traffic must use to access the appropriate network devices. By default, VTP pruning is disabled. 
Reference: http://www.cisco.com/c/en/us/td/docs/switches/lan/catalyst6500/ios/12-2SX/configuration/guide/book/vtp.html#wp1020444