Table Of Contents
Discrepancy Reporting
Understanding Discrepancy Reporting
Physical Discrepancies
Logical Discrepancies
Configuring Discrepancy Reporting and Syslog Message Generation
Viewing Physical Discrepancy Reports
Viewing Logical Discrepancy Reports
Interpreting Discrepancies
Interpreting Physical Discrepancies
Link Duplex Mismatch
Link Speed Mismatch
Trunk/Non-Trunk Mismatch
Port in Error Disabled State
PortFastEnabled on Trunk Port
High Availability Disabled
CDP Enabled on Access Ports
BackboneFast Disabled
UplinkFast Disabled
UDLD Disabled
BPDU Guard Disabled
STP Enabled on Access Ports
Auto Channel
No Channel
Auto Trunk
No Trunk
Interpreting Logical Discrepancies
Duplicate SysName
Trunk VLANs Mismatch
Native VLANs Mismatch
VLAN Name Conflict
VLAN Index Conflict
Trunk VLAN Protocol Mismatch
VTP Disconnected Domain
No VTP Server in Domain
EtherChannel Port Spanning Tree Not Disabled
ATM-VLAN Without Entry in LE Config Server
ATM-VLAN With LE Server Without Entry in LE Config Server
More Than One LE Config Server in a Single ATM Domain
Partitioned ATM-VLAN
DRiP Enabled VLAN
Trunk Negotiation Enabled
Discrepancy Reporting
The Discrepancy Reporting module allows you to view the physical and logical discrepancies in your network. This chapter contains the following:
•
Understanding Discrepancy Reporting
•
Interpreting Discrepancies
Understanding Discrepancy Reporting
This feature offers reports on network inconsistencies, anomalies or misconfiguration in the physical and logical layout in the discovered network. This makes it easy to identify configuration errors such as link-speed mismatches on either end of a connection. This chapter contains the following:
•
Physical Discrepancies
•
Logical Discrepancies
•
Configuring Discrepancy Reporting and Syslog Message Generation
•
Viewing Physical Discrepancy Reports
•
Viewing Logical Discrepancy Reports
Physical Discrepancies
Physical discrepancies are potential misconfigurations in the physical layout of your network. Physical discrepancies include mismatches in link speed, trunk configuration, or duplex mode on two ends of a link.
For example, full duplex configured on one side of a link and half duplex configured on the other side. Table 6-1 lists the physical discrepancies reported by Campus Manager.
Table 6-1 Physical Discrepancies
Field
|
Discrepancy
|
Description
|
Physical > Link > Duplex
|
Link Duplex Mismatch
|
Full-duplex versus half-duplex on either side of a link
|
Physical > Link > Speed
|
Link Speed Mismatch
|
Different link speed on either side of a link (for 10/100 ports or for any group of links)
|
Physical > Link > Trunk
|
Trunk/nonTrunk Mismatch
|
Trunking ports versus nontrunking ports on either side of a link
|
Physical > Port > ErrDisabled
|
Port in ErrorDisabled State
|
Port is in Error Disabled state caused by erroneous traffic
|
Physical > Port > PortFastEnabled
|
PortFastEnabled on Trunk Port
|
A port configured for trunk is in Spanning Tree PortFastEnabled state
|
Physical > High AvailabilityDisabled
|
High Availability Disabled
|
High Availability Feature is disabled in a device when it has more than one Supervisor Card
|
Physical > CDPEnabledon AccessPort
|
CDP Enabled on Access Port
|
An access port of a device is enabled for CDP
|
Physical > Device > BackboneFastDisabled
|
BackboneFast Disabled
|
BackboneFast feature is disabled on a device
|
Physical > Device > UplinkFastDisabled
|
UplinkFast Disabled
|
UplinkFast feature is disabled on a device
|
Physical > Port > UDLDDisabled
|
UDLD Disabled
|
Unidirectional Link Detection feature is disabled on a device
|
Physical > Port > STPEnabledonAccess Ports
|
STP Enabled on Access Ports
|
An access port of a device in which STP is enabled
|
Physical > Port > BPDUGuardDisabled
|
BPDU Guard Disabled
|
BPDU Guard Feature is disabled on a port
|
Physical > Port > AutoChannel
|
Auto Channel
|
A port is configured for auto mode, and it is part of channel
|
Physical > Port > NoChannel
|
No Channel
|
A port is configured for desirable mode, and it is not part of channel
|
Physical > Port > AutoTrunk
|
Auto Trunk
|
Trunk Mode is set to Auto, but port is trunking
|
Physical > Port > NoTrunk
|
No Trunk
|
Trunk mode set to desirable, but port is not trunking
|
Logical Discrepancies
Logical discrepancies include inconsistent or incorrect settings in VTP domains, VLANS, and ATM LANE components.
For example, an ATM VLAN that has no entry in the LECS or if there is a VTP client and no VTP server. Table 6-2 lists the logical discrepancies reported by Campus Manager.
Table 6-2 Logical Discrepancies
Field
|
Discrepancy
|
Description
|
General > DuplicateSysName
|
Duplicate SysName
|
More than one device with the same sysname (SystemName) on the Network.
|
LANE > ATM-VLAN > NoEntryInLECS
|
ATM-VLAN with no entry in LE Config Server
|
ATM-VLAN having no entry in LE Config Server
|
LANE > ATM-VLAN > NoLESBUSEntryInLECS
|
ATM-VLAN with LE Server having no entry in LE Config Server
|
ATM-VLAN with LE Server having no entry in LE Config Server
|
LANE > ATM-VLAN > Partitioned
|
Partitioned ATM-VLAN
|
Partitioned ATM-VLAN
|
LANE > LECS > MultiMaster
|
More than one LE Config Server in a single ATM Domain
|
More than one LE Config Server present in a single ATM Domain
|
VLAN > Domain > Disconnect
|
VTP Disconnected Domain
|
VTP Disconnected Domain
|
VLAN > Domain > NoServerWithClients
|
No VTP Server in Domain
|
No VTP Server configured in Domain
|
VLAN > DripEnabled
|
DRiP enabled VLAN
|
DRiP enabled VLAN
|
VLAN > EtherChannelPort > SpanningTree
|
EtherChannel Port Spanning Tree not disabled
|
EtherChannel Port Spanning Tree not disabled
|
VLAN > Link > Multi
|
Trunk VLANs Mismatch
|
Trunk VLANs Mismatch
|
VLAN > Link > Protocol
|
Trunk VLAN Protocol Mismatch
|
Trunk VLAN Protocol Mismatch
|
VLAN > Link > Single
|
Native VLANs Mismatch
|
Native VLANs Mismatch
|
VLAN > Link > TrunkNegotiationEnabled
|
Trunk Negotiation Enabled
|
DTP enabled on trunk port across VTP boundary
|
VLAN > Pair > Index
|
VLAN Index Conflict
|
VLAN Index Conflict
|
VLAN > Pair > Name
|
VLAN Name Conflict
|
VLAN Name Conflict
|
Configuring Discrepancy Reporting and Syslog Message Generation
You can customize the Discrepancy Report to display only those discrepancies about which you want to be notified.
To customize the reports:
Step 1
Select Campus Manager > Administration > Network Discrepancies.
The Network Discrepancies window appears.
Step 2
Click Configure to include or exclude discrepancies to be reported, and also to configure syslog.
The Configure Network Discrepancies dialog box appears.
Step 3
Select the discrepancies to be included in the Discrepancy Report.
•
To include a discrepancy in the Discrepancy Reports, check the box next to it.
If you check all the boxes, a report appears with all discrepancies in the network.
•
To exclude a discrepancy from the Discrepancy Reports, uncheck the box.
Step 4
Select the Configure Syslog check box and click Next.
The list of selected discrepancies appears.
Step 5
Select the Send Syslogs check box and enter the name of the server in the Syslog Server field.
Step 6
Select the discrepancies for which you want to generate syslog messages and click Next.
A summary of the selected discrepancies appears.
Step 7
Click Finish.
Viewing Physical Discrepancy Reports
Discrepancy reports can be viewed using either of the following methods:
•
From the CiscoWorks Homepage:
Select Campus Manager > Discrepancy Reports > Physical Discrepancy Report.
Or
•
From a network topology view:
To view physical discrepancies for the entire network, from the LAN Edge or Layer 2 Network View window, select Reports > Discrepancies. It displays any link-setting mismatches that might need to be corrected on devices.
You can also display physical discrepancies for a specific ATM or VTFI domain by selecting the discrepancy filters within the Network View window for that domain.
Viewing Logical Discrepancy Reports
You can display logical discrepancies to identify inconsistencies in the logical setup of the VTP Domains, VLANs, and LANE components in your network.
To display these discrepancies, you can do either of the following:
•
From the CiscoWorks Homepage:
Select Campus Manager > Discrepancy Reports > Logical Discrepancy Report.
Or
•
Follow this procedure in Topology Services:
Step 1
Select Reports > Discrepancies in Topology Services.
The Logical Discrepancy report appears.
•
To print this report, select File > Print from the Discrepancy Report menu.
•
To save the summary of discrepancies as a file, select File > Export > Summary from the Discrepancy Report menu bar.
•
To save the summary and details of discrepancies as a file, select File > Export > Details from the Discrepancy Report menu.
Step 2
Select a discrepancy and click Details for more information.
Interpreting Discrepancies
When interpreting the discrepancy report, consider that some configurations may appear as discrepancies. If you had planned to configure your network in this way, you can ignore the discrepancies. This section contains the floowing topics:
•
Interpreting Physical Discrepancies
•
Interpreting Logical Discrepancies
Interpreting Physical Discrepancies
Physical discrepancies are potential misconfigurations in the physical layout of your network. This section contains information on the physical discrepancies reported in Campus Manager 4.0.6. It gives the description of the discrepancy, the impact it has on the network, and ways to resolve it. This section contains:
•
Link Duplex Mismatch
•
Link Speed Mismatch
•
Trunk/Non-Trunk Mismatch
•
Port in Error Disabled State
•
PortFastEnabled on Trunk Port
•
High Availability Disabled
•
CDP Enabled on Access Ports
•
BackboneFast Disabled
•
UplinkFast Disabled
•
UDLD Disabled
•
BPDU Guard Disabled
•
STP Enabled on Access Ports
•
Auto Channel
•
No Channel
•
Auto Trunk
•
No Trunk
Link Duplex Mismatch
Campus Manager reports a discrepancy when there is a duplex mismatch between links.
Duplex mismatch on 10/100Mb Ethernet links occurs when one port on the link is operating at half-duplex while the other port is operating at full-duplex.
This happens when one or both ports on a link are reset and the auto-negotiation process does not result in both link partners having the same configuration. It also happens when you reconfigure one side of a link and do not reconfigure the other side.
Impact
Unlike half-duplex, which must wait until no other devices are transmitting on the same LAN segment, a full-duplex device will transmit whenever it has something to send, regardless of other devices.
If this transmission occurs while the half-duplex device is transmitting, the half-duplex device will consider this either a collision (during the slot time), or a late collision (after the slot time). Since the full-duplex side does not expect collisions, it does not realize that it must retransmit that dropped packet.
A low percentage rate of collisions are normal with half-duplex, but not with full-duplex. If the switch port receives a lot of late collisions, this usually indicates a duplex mismatch problem.
Fix
To fix the discrepancy on switches using Cisco IOS, enter the following at the CLI:
duplex auto
end
where auto enables the autonegotiation capability.
To fix the discrepancy on switches using Catalyst operating system, enter the following at the CLI:
set port duplex mod/port auto
end
where:
•
mod/port refers to the number of the module and the port on the module
•
auto specifies autonegotiation for transmission speed and duplex mode on 10/100 Fast Ethernet ports
Link Speed Mismatch
Campus Manager reports a discrepancy when there is a mismatch in the link speeds, that is, different link speed on either side of a link (for 10/100 ports—or for any group of links).
The IEEE 802.3u autonegotiation protocol manages the switch settings for speed (10 Mbps or 100 Mbps) and duplex (half or full). There are situations when this protocol can incorrectly align these settings, reducing performance. A mismatch occurs under these circumstances:
•
A manually-set speed or duplex parameter is different from the manually set speed or duplex parameter on the connected port.
•
A port is in Autonegotiate mode and the connected port is set to full duplex with no autonegotiation.
Impact
Link speed mismatch results in reduced performance of the link.
Fix
To fix the discrepancy on switches using Cisco IOS, enter the following at the CLI:
speed auto
end
where auto enables the autonegotiation capability.
To fix the discrepancy on switches using Catalyst operating system, enter the following at the CLI:
set port speed mod/port auto
where:
•
mod/port refers to the number of the module and the port on the module
•
auto specifies autonegotiation for transmission speed and duplex mode on 10/100 Fast Ethernet ports
Trunk/Non-Trunk Mismatch
Campus Manager reports a discrepancy when there are trunking ports and non-trunking ports on either side of a link. This happens when one end of the trunk is set to On, and the other end is set to Off.
Impact
This results in the trunk not coming up, and there would be no traffic flow across the link.
Fix
To fix the discrepancy on switches using Catalyst operating system, enter the following at the CLI:
set trunk mod/port desirable
where:
•
desirable causes the port to negotiate actively with the neighboring port to become a trunk link
•
mod/port specifies the number of the module and the port or ports on the module
To fix the discrepancy on switches using Cisco IOS, enter the following at the CLI:
switchport mode dynamic desirable
end
where dynamic desirable specifies an interface that actively attempts to convert the link to a trunk link.
Port in Error Disabled State
Campus Manager reports a discrepancy when one or more of the switch ports in the discovered network have a status of errDisable.
Causes of errDisable
A port enters errdisable state for any of the following reasons:
•
Channel misconfiguration
•
Duplex mismatch
•
BPDU port-guard
•
UDLD
Impact
When a port is error-disabled, it is effectively shut down and no traffic is sent or received on that port. The port LED is set to the color orange and when you enter the show port command, the port status shows errdisable.
Fix
In order to recover from errDisable you should:
Step 1
Identify and fix whatever caused the ports to become error-disabled (cable, NICs, EtherChannel, and so on).
Step 2
Re-enable the port.
For more information on the errDisable state, see the document Recovering From errDisable Port State on the CatOS Platforms at the following location:
http://www.cisco.com/en/US/partner/tech/tk389/tk214/technologies_tech_note09186a0080093dcb.shtml
PortFastEnabled on Trunk Port
Campus Manager reports a discrepancy when PortFast is enabled on trunk ports.
PortFast causes a spanning tree port to immediately enter the forwarding state, bypassing the listening and learning states.
You must disable STP PortFast for switch-switch links. This is because, if you enable PortFast on a port that is connected to another Layer 2 device, such as a switch, you might create network loops.
Impact
If you enable PortFast on ports that connect two switches, spanning tree loops can occur if Bridge Protocol Data Units (BPDUs) are being transmitted and received on those ports.
Fix
To fix the discrepancy on switches using Catalyst operating system, enter the following at the CLI:
set spantree portfast mod/port disable
where disable disables the spanning tree PortFast-start feature on the port.
To fix the discrepancy on switches using Cisco IOS, enter the following at the CLI:
no spanning-tree portfast
end
This command disables PortFast on the given port.
High Availability Disabled
Enabling High Availability on switches is applicable only for Cisco Catalyst 6000 devices. Campus Manager reports a discrepancy when there are two supervisor engines in Cisco Catalyst 6000 devices and High Availability is not enabled.
Impact
High Availability:
•
Is a critical requirement for most networks. Switch downtime must be minimal to ensure maximum productivity in a network.
•
Allows you to minimize the switch-over time from active supervisor engine to the standby supervisor engine, if the active supervisor engine fails.
•
Allows the active supervisor engine to communicate with the standby supervisor engine, keeping feature protocol states synchronized.
•
Provides a versioning option that allows you to run different software images on the active and standby supervisor engines.
You can enable High Availability using Command Line Interface (CLI).
Fix
As a general practice with redundant supervisors, we recommend that you enable High Availability feature for normal operation.
To fix the discrepancy on switches using Catalyst operating system, enter the following at the CLI:
set system highavailability enable
CDP Enabled on Access Ports
Campus Manager reports a discrepancy when Cisco Discovery Protocol (CDP) is enabled on the access port of a switch.
CDP is enabled by default and is essential to gain visibility of adjacent devices and for troubleshooting. It is also used by network management applications to build Layer 2 topology maps.
Impact
In parts of the network where a high level of security is required (such as Internet-facing de-militarized zones), you should turn off CDP.
Fix
To fix the discrepancy on switches using Catalyst operating system, enter the following at the CLI:
set cdp disable mod/port
To fix the discrepancy on switches using Cisco IOS, enter the following at the CLI:
no cdp enable
BackboneFast Disabled
Campus Manager reports a discrepancy when BackboneFast is enabled on one of the switches and not enabled on all other switches in a switch cloud.
Cisco recommends that BackboneFast be enabled on all switches running STP. It can be added without disruption to a production network.
Impact
If you do not enable BackboneFast on all devices, it might lead to undesirable effects on the spanning tree operation.
BackboneFast provides rapid convergence from indirect link failures. By adding functionality to STP, you can reduce convergence times from the default of 50 seconds to 30 seconds.
Fix
Enable BackboneFast on all switches in a switch cloud.
To fix the discrepancy on switches using Catalyst operating system, enter the following at the CLI:
set spantree backbonefast enable
To fix the discrepancy on switches using Cisco IOS, enter the following at the CLI:
spanning-tree backbonefast
UplinkFast Disabled
Campus Manager reports a discrepancy when UplinkFast is not enabled on switches.
Note
This discrepancy is not applicable if the device is not an access layer switch.
We recommend that you enable UplinkFast for switches with blocked ports, typically at the access layer. Do not use on switches without the implied topology knowledge of a backup root link—typically, distribution and core switches in Cisco's multilayer design. You can add this without disruption to a production network.
Impact
UplinkFast provides fast STP convergence after a direct link failure in the network access layer. It operates without modifying STP, and its purpose is to speed up convergence time in a specific circumstance to less than three seconds, rather than the typical 30-second delay.
Fix
Enable UplinkFast on all access layer switches.
To enable Uplink Fast on Catalyst operating system:
Step 1
Enter the command:
set spantree uplinkfast enable
Step 2
Enter this command to check the status:
show spantree uplinkfast
To enable Uplink Fast on Cisco IOS:
Step 1
Enter the command:
spanning-tree uplinkfast
Step 2
Enter this command to check the status:
show spanning-tree uplinkfast
For more information on Spanning Tree related configuration, see the document Configuring Spanning Tree PortFast, UplinkFast, and BackboneFast at the following location:
http://www.cisco.com/univercd/cc/td/doc/product/lan/cat6000/sw_8_4/confg_gd/stp_enha.htm
UDLD Disabled
Campus Manager reports a discrepancy if UniDirectional Link Detection (UDLD) is disabled on link ports.
Impact
If you disable UDLD, it could result in Spanning Tree loops.
Unidirectional links are often caused by a failure not detected on a fiber link, or by a problem with a transceiver.
To fix the discrepancy on switches using Catalyst operating system, enter the following at the CLI:
set udld enable mod/port
where enable enables the UDLD information display.
To fix the discrepancy on switches using Cisco IOS, enter the following at the CLI:
udld port
end
This command enables UDLD in normal mode by default on all interfaces.
BPDU Guard Disabled
Campus Manager reports a discrepancy if PortFast is enabled and BPDUGuard is not enabled on a port.
BPDU-Guard prevents spanning-tree loops by moving a port into the errdisable state when a BPDU is received on that port. When you enable BPDU-Guard on the switch, spanning tree shuts down the interfaces that receive BPDUs instead of putting the interfaces into the spanning-tree blocking state.
Impact
Cisco recommends that you enable BPDUGuard to block incoming BPDUs on edge devices (end-hosts). The Cisco BPDUGuard feature, when enabled, informs the switch to disable PortFast ports if a BPDU is received on those ports.
BDPUGuard can be enabled on each port or globally. When you enable BPDUGuard globally, it applies to all PortFast-enabled ports on the switch.
Fix
To fix the discrepancy on switches using Catalyst operating system, enter the following at the CLI:
set spantree bpdu-guard mod/port enable
where:
•
mod/port specifies the number of the module and the port on the module
•
enable enables BPDUGuard
To fix the discrepancy on switches using Cisco IOS, enter the following at the CLI:
spanning-tree bpduguard enable
end
where enable enables BPDUGuard on the particular interface.
STP Enabled on Access Ports
Campus Manager reports a discrepancy when STP is enabled on access ports.
Impact
BPDU filtering allows you to avoid transmitting BPDUs on PortFast-enabled ports that are connected to an end system. When you enable PortFast on the switch, spanning tree places ports in the forwarding state immediately, instead of going through the listening, learning, and forwarding states.
By default, spanning tree sends BPDUs from all ports regardless of whether PortFast is enabled. BDPUFilter can be enabled for each port or globally. When you enable BPDUFilter globally, it applies to all PortFast-enabled ports on the switch.
When you disable PortFast on a port, the BPDU Filter that was globally enabled on the PortFast enabled port is also disabled.
Fix
To fix the discrepancy on switches using Catalyst operating system, enter the following at the CLI:
set spantree bpdu-filter mod/port enable
where:
•
mod/port specifies the number of the module and the port on the module
•
enable enables BPDU packet filtering
To fix the discrepancy on switches using Cisco IOS, enter the following at the CLI:
spanning-tree bpdufilter enable
end
where enable enables BPDU Filtering on the particular interface.
Auto Channel
Campus Manager reports a discrepancy when a channel port is in auto mode.
There are four user-configurable channel modes:
•
On
•
Off
•
Auto
•
Desirable
Port Aggregation Protocol (PAgP) packets are exchanged only between ports in Auto and Desirable mode. Ports configured in On or Off mode do not exchange PAgP packets.
For switches to which you want to form an EtherChannel, it is best to have both switches set to Desirable mode. This gives the most robust behavior if one side or the other encounters error situations or is reset. The default mode of the channel is Auto.
Both the Auto and Desirable modes allow ports to negotiate with connected ports to determine if they can form a channel. The determination is based on criteria such as port speed, trunking state, and native VLAN.
Ports can form an EtherChannel when they are in different channel modes as long as the modes are compatible.
This list provides examples:
•
A port in Desirable mode can successfully form an EtherChannel with another port that is in Desirable or Auto mode.
•
A port in Auto mode can form an EtherChannel with another port in Desirable mode.
•
A port in Auto mode cannot form an EtherChannel with another port that is also in Auto mode, since neither port initiates negotiation.
•
A port in On mode can form a channel only with a port in On mode because ports in On mode do not exchange PAgP packets.
•
A port in Off mode cannot form a channel with any port.
Impact
Channel port set to Auto mode is considered a discrepancy because it is not the recommended configuration. Cisco recommends that you set the channel port to Desirable mode. There is no serious impact on the network.
Fix
Set the channel port to Desirable mode.
No Channel
Campus Manager reports a discrepancy when a non-channel port is in Desirable mode.
There are four user-configurable channel modes:
•
On
•
Off
•
Auto
•
Desirable
Port Aggregation Protocol (PAgP) packets are exchanged only between ports in Auto and Desirable mode. Ports configured in on or off mode do not exchange PAgP packets.
For switches to which you want to form an EtherChannel, it is best to have both switches set to Desirable mode. This gives the most robust behavior if one side or the other encounters error situations or is reset. The default mode of the channel is Auto.
Both the Auto and Desirable modes allow ports to negotiate with connected ports to determine if they can form a channel. The determination is based on criteria such as port speed, trunking state, and native VLAN.
Ports can form an EtherChannel when they are in different channel modes as long as the modes are compatible.
This list provides examples:
•
A port in desirable mode can successfully form an EtherChannel with another port that is in Desirable or Auto mode.
•
A port in Auto mode can form an EtherChannel with another port in Desirable mode.
•
A port in Auto mode cannot form an EtherChannel with another port that is also in Auto mode, since neither port initiates negotiation.
•
A port in On mode can form a channel only with a port in On mode because ports in On mode do not exchange PAgP packets.
•
A port in Off mode cannot form a channel with any port.
Impact
When a non-channel port is in Desirable mode, the links will not be efficiently used.
Fix
Set the non-channel port to Auto mode.
Auto Trunk
Campus Manager reports a discrepancy when trunk ports are set to Auto mode.
Impact
Cisco recommends an explicit trunk configuration of Desirable at both ends. Auto mode indicates a static property and the port will not initiate the trunking link, if the neighbor does not initiate it. See Table 6-3 for different trunk mode combinations.
Table 6-3 Trunking Configuration 1
Modes
|
On
|
Auto
|
Desirable
|
Nonegotiate
|
Off
|
On
|
None.
(Trunking)
|
Reports discrepancy.
(Trunking)
|
None.
(Trunking)
|
None.
(Trunking)
|
Reports discrepancy.
(Not Trunking)
|
Auto
|
Reports discrepancy.
(Trunking)
|
None.
(Not Trunking)
|
Reports discrepancy.
(Trunking)
|
Reports discrepancy.
(Not Trunking)
|
None.
(Not Trunking)
|
Desirable
|
None.
(Trunking)
|
Reports discrepancy.
(Trunking)
|
None.
(Trunking)
|
Reports discrepancy.
(Not Trunking)
|
Reports discrepancy.
(Not Trunking)
|
Nonegotiate
|
None.
(Trunking)
|
Reports discrepancy.
(Not Trunking)
|
Reports discrepancy.
(Not Trunking)
|
None.
(Trunking)
|
Reports discrepancy.
(Not Trunking)
|
Off
|
Reports discrepancy.
(Not Trunking)
|
None.
(Not Trunking)
|
Reports discrepancy.
(Not Trunking)
|
Reports discrepancy.
(Not Trunking)
|
None.
(Not Trunking)
|
Fix
Set both ends of trunk ports to Desirable mode. You cannot fix this discrepancy through Campus Manager.
Enter the following command to set Desirable mode:
set trunk mod/port desirable ISL | dot1q
No Trunk
Campus Manager reports a discrepancy when non-trunk ports are set to Desirable mode.
Impact
Cisco recommends that you set trunk to Off on all non-trunk ports. This helps eliminate wasted negotiation time when bringing host ports up. If a non-trunk port is set to Desirable, it attempts to become a trunk port if the neighboring port is in Desirable or Auto mode, although that is not the intended behavior.
Fix
Set the trunk mode to Off on all non-trunk ports.
Table 6-3 lists all possible combinations of trunk mode configurations and when Campus Manager reports a discrepancy.
Interpreting Logical Discrepancies
Logical discrepancies identify inconsistencies in the logical setup of the VTP Domains, VLANs, and LANE components in your network. This section contains information on the logical discrepancies reported in Campus Manager 4.0.6. It gives the description of the discrepancy, the impact it has on the network, and ways to resolve it. This section contains:
•
Duplicate SysName
•
Trunk VLANs Mismatch
•
Native VLANs Mismatch
•
VLAN Name Conflict
•
VLAN Index Conflict
•
Trunk VLAN Protocol Mismatch
•
VTP Disconnected Domain
•
No VTP Server in Domain
•
EtherChannel Port Spanning Tree Not Disabled
•
ATM-VLAN Without Entry in LE Config Server
•
ATM-VLAN With LE Server Without Entry in LE Config Server
•
More Than One LE Config Server in a Single ATM Domain
•
Partitioned ATM-VLAN
•
DRiP Enabled VLAN
•
Trunk Negotiation Enabled
Duplicate SysName
Campus Manager reports a discrepancy when it discovers two devices with the same SysName. Campus Manager stores the device details of only one of the two devices.
Impact
Campus Manager manages only one of these devices.
Fix
Assign unique SysName for all devices in the network.
Trunk VLANs Mismatch
Campus Manager reports a discrepancy when the list of active or allowed VLANs between the two ends of a trunk do not match.
Impact
The trunk remains operational but the network traffic across the link is affected.
Fix
You can resolve this by modifying the list of allowed VLANs between the two ends of a trunk and ensuring that there is no mismatch.
Native VLANs Mismatch
Campus Manager reports a discrepancy when when the native VLANs of all ports in a trunk do not match.
This mismatch occurs when you have created a trunk port to connect another switch, and both ends are in different native VLANs.
Note
This discrepancy is applicable only for trunks that use 802.1q.
Impact
The native VLAN must match on both sides of the trunk link, otherwise the traffic flow across the link is affected. The trunk continues to remain operational.
Fix
If you have altered the default native VLAN configuration, ensure that all trunks have the same native VLAN. Use the set vlan command for Cisco Catalyst operating system switches or the switchport trunk native vlan command for Cisco IOS switches to specify the native VLAN.
For more information on configuring VLANs, see the document Creating and Maintaining VLANs at the following location:
http://www.cisco.com/en/US/partner/products/hw/switches/ps637/
products_configuration_guide_chapter09186a008007f261.html
VLAN Name Conflict
Campus Manager reports a discrepancy when there is a conflict in the VLAN Name. A VLAN Name conflict occurs in case of a VTP domain which has Server mode and Transparent/off mode devices, where a VLAN part of the transparent mode device in the domain has the same name as VLAN part of the server mode device in the domain.
Impact
There is no serious impact on the network connectivity. It is considered as a discrepancy because Campus Manager cannot manage a VTP domain with devices where a VLAN part of the transparent mode device in the domain has the same name as VLAN part of the server mode device in the domain.
Fix
Resolve the conflict by assigning different names for the VLAN part of the transparent mode and the server mode devices.
VLAN Index Conflict
Campus Manager reports a discrepancy when there is a conflict in the VLAN Index. A VLAN Index conflict occurs in case of a VTP domain which has Server mode and Transparent/off mode devices, where a same VLAN index has different VLAN name in transparent and server mode devices in the domain.
Impact
There is no serious impact on the network connectivity. It is considered as a discrepancy because Campus Manager cannot manage a VTP domain where the same VLAN index has different VLAN names in transparent and server mode devices.
Fix
Assign the same name for a VLAN Index in both the transparent and server modes of the VTP domain.
Trunk VLAN Protocol Mismatch
Campus Manager reports a discrepancy when different trunk encapsulations are set on the two ends of a trunk.
For example, when one end of a trunk is configured as ISL and the other as 802.1q, Campus Manager reports a discrepancy.
ISL and 802.1q are the different encapsulation types that you can configure in a trunk VLAN.
Impact
The trunk remains operational when the trunk mode is set to On or No-negotiate with mismatching encapsulation types. However, the network traffic across the link is affected because of the mismatch.
Fix
Configure the same encapsulation type on both ends of the trunk.
VTP Disconnected Domain
Campus Manager reports a discrepancy if the devices that are part of the same VTP domain have different VTP configuration revision numbers. When a switch in the same VTP domain has a higher configuration revision number compared to the other switches, it could overwrite your server-configured switch with incorrect information.
Impact
The VLAN information is not dynamically shared across the VTP domain.
Fix
Ensure that you configure VTP Configuration Revision number consistently across devices of the same VTP domain.
No VTP Server in Domain
Campus Manager reports a discrepancy when there is no VTP Server configured in a VTP domain.
You can configure a switch to operate in any one of these VTP modes—Server, Client, Transparent, and Off. Primary and secondary servers are two types of servers that may exist on an instance in the VTPv3 domain.
A VTP client cannot store the VLAN information. When a VTP client boots, it needs to reacquire the entire configuration that is propagated by VTP.
The primary server can initiate or change the VTP configuration. The main purpose of a VTP secondary server is to back up the configuration that is propagated over the network.
Impact
Campus Manager reports a discrepancy when an existing VTP server or primary server goes down and there is no alternative or backup server.
This can occur in a VTPv2 or VTPv3 domain that has only client mode devices. This could happen when the existing primary server or server mode device has gone down temporarily and if the server mode device does not come up.
If you do not configure atleast one server, the devices become unreachable. Campus Manager discovers only the client-mode devices in the domain and ignores the rest.
Fix
Configure atleast one device as server in a VTP domain. If the device you have configured as server is temporarily down, configure another device as server.
For more information on VTP domain, see the document Configuring VTP at the following location:
http://www.cisco.com/univercd/cc/td/doc/product/lan/cat6000/sw_8_1/
confg_gd/vtp.htm
EtherChannel Port Spanning Tree Not Disabled
Campus Manager reports a discrepancy when Spanning Tree is enabled on EtherChannel links.
Spanning Tree Protocol is not supported with Catalyst software release 2.3 and lower. Therefore, disable Spanning Tree on switches with active VLANs that span Fast EtherChannel connections.
For Catalyst software release 3.1 and higher, configure Spanning Tree on Fast EtherChannel links.
ATM-VLAN Without Entry in LE Config Server
Campus Manager reports a discrepancy when the LECS database does not have corresponding entry for a LANE Broadcast and Unknown Server (BUS).
Impact
When the LECS database does not have an entry for a LANE BUS, the LAN Emulation Clients (LECs) cannot contact the LAN Emulation Server (LES) BUS. This will affect the network connectivity.
Fix
Create an entry for the LANE BUS in the LECS database.
For more information on ATM networks, see the document Designing ATM Internetworks at the following location:
http://www.cisco.com/univercd/cc/td/doc/cisintwk/idg4/nd2008.htm
ATM-VLAN With LE Server Without Entry in LE Config Server
Campus Manager reports a discrepancy when there is no entry for an Emulated LAN (ELAN) in the LAN Emulation Configuration Server (LECS).
The LECS maintains a database of ELANs and the ATM addresses of the LAN Emulation Servers (LES) that control the ELANs.
Impact
If there is no entry for an ELAN in the LECS database, the LANE clients in the corresponding ELAN will not be able to join the ELAN. This affects the network connectivity and flow of traffic.
Fix
Create an entry for the ELAN in the LECS database.
For more information on ATM networks, see the document Designing ATM Internetworks at the following location:
http://www.cisco.com/univercd/cc/td/doc/cisintwk/idg4/nd2008.htm
More Than One LE Config Server in a Single ATM Domain
Campus Manager reports a discrepancy when more than one LECS is found in an ATM cloud in a LANE 1.0 specification.
Impact
When there is more than one LECS in an ATM cloud, it results in faulty and inconsistent behavior of the LANE. The network connectivity is affected.
Fix
Ensure that there is only one LECS in an ATM cloud.
For more information on ATM networks, see the document Designing ATM Internetworks at the following location:
http://www.cisco.com/univercd/cc/td/doc/cisintwk/idg4/nd2008.htm
Partitioned ATM-VLAN
Campus Manager reports a discrepancy when there is a partitioned ATM-VLAN, that is, when clients of one ELAN have joined a different LES.
Impact
The clients of the ELAN which have become part of another LES cannot communicate with other clients. The network connectivity in the ATM-VLAN is disrupted.
For more information on ATM networks, see the document Designing ATM Internetworks at the following location:
http://www.cisco.com/univercd/cc/td/doc/cisintwk/idg4/nd2008.htm
DRiP Enabled VLAN
Campus Manager reports a discrepancy when there are two identical Token Ring Concentrator Relay Function (TrcRF) in a Token Ring Bridge Relay Function (TrBRF).
The Duplicate Ring Protocol (DRiP) is a Cisco proprietary protocol that runs on Cisco routers and switches that support switched VLAN networking and is used to identify active Token Ring VLANs.
DRiP maintains the status of TrCRFs and uses this information to determine whether there are multiple TrCRFs active in a TrBRF.
Impact
If you enable TrCRF on more than one switch or router, the ports associated with the TrCRF are disabled on all switches. A router will not disable the internal ring used for source-route bridging, and for routing source-routed traffic.
Instead, the router displays the following error message to indicate that two identical TrCRFs exist:
DRIP conflict with CRF <vlan-id>
Fix
Assign a unique ring number for each TrCRF.
Trunk Negotiation Enabled
Campus Manager reports a discrepancy when trunk mode on any one end of the trunk link is set to Auto or Desirable.
Dynamic Trunking Protocol (DTP) cannot be used for trunk negotiation across VTP domain boundary. This occurs when trunk mode on both sides has any of the following combination:
•
On/Auto
•
On/Desirable
•
Desirable/Auto
•
Desirable/Desirable
•
Off/Desirable
Impact
Trunk negotiation across VTP boundary (that is, trunk link connecting two devices which are part of different VTP domains) fails.
Fix
To fix the discrepancy on switches using Cisco IOS, enter the following at the CLI:
switchport trunk encapsulation dot1q | isl
switchport mode trunk
end
To fix the discrepancy on switches using Catalyst operating system, enter the following at the CLI:
set trunk mod/port on Dot1Q
Or
set trunk mod/port on ISL