Networking Knowledge Base

Core IssueThe Open Shortest Path First (OSPF) forwarding address concept allows another router's IP address to be specified as the forwarding address to avoid an extra hop in the path to the destination. This is typically seen when the next-hop route...

Core issueThe Common Services/Common Management Foundation (CMF) database, where job information is stored, could be corrupted.ResolutionInformation about the jobs are stored in the CMF database. Reset the password for CMF database so Job and Resourc...

Core issueThis message indicates that the module passed the diagnostic self-test and is online. [dec] is the module number. You are experiencing a silent reload on the line card. A silent reload occurs when a line card experiences a CPU exception and...

Core IssueWhen Open Shortest Path First (OSPF) is enabled on a router or when a router configured for OSPF is powered up, OSPF neighbors are not known and the OSPF state is said to be init. The router then discovers other OSPF speaking routers and sy...

Core issueThis problem is observed in these conditions:When switches are stackedWhen IP routing is disabledWhen the master switch is changed This can be due to a master failure, a change in master priority, or a reload.This slow, constant memory leak...

Core issueCisco CallManager must have SNMP configured to send or receive traps, and to reply to queries by Network Management Systems.ResolutionThis is a list of Management Information Bases (MIB) supported by Cisco CallManager:CISCO-CCM-MIBCISCO-CDP...

IntroductionDescriptionGLBP featuresError - Debug glbp errorsReference IntroductionThe Gateway Load Balancing Protocol feature provides automatic router backup for IP hosts configured with a single default gateway on an IEEE 802.3 LAN. Multiple first...

ResolutionEnhanced Interior Gateway Routing Protocol (EIGRP) is a Cisco proprietary enhanced distance vector routing protocol, relying on the Diffused Update Algorithm (DUAL) to calculate the shortest path to a destination. EIGRP can redistribute sta...

Core issueThe error message can look similar to this:%C4K_SWITCHINGENGINEMAN-3-TXCNTMEMORYPARITY: Parity mismatch in transmit count memory, addr=E18D, reg bits=8000E18D, total=1There is a soft parity error in packet memory, and it can be transient or...

Core IssueCisco routers such as the 2500, AS5200, and some 1600 series, run the Cisco IOS  from the Flash rather than from RAM. Because of this, Flash is in a Read Only state while the Cisco IOS Software is running on the router. Attempting to write ...

Core IssueIn most cases, Open Shortest Path First (OSPF) finds a discrepancy in the database, so it does not install the route in the routing table. Often, you will  receive the Adv Router is not-reachable  error  message, indicating that the router ...

ResolutionThis is an example of how to map ifIndex to an interface on Cisco IOS :snmpwalk -c public ponch ifNameIF-MIB::ifName.1 = STRING: AT2/0IF-MIB::ifName.2 = STRING: Et0/0IF-MIB::ifName.3 = STRING: Se0/0IF-MIB::ifName.4 = STRING: BR0/0where:1 = ...

Core issueSimple Network Management Protocol (SNMP) MIB provides memory utilization for Catalyst switches.ResolutionTo utilize memory, use CISCO-MEMORY-POOL.For more information, refer to these documents:MIB       Object Identifier (OID)       For mo...

Core issueA Catalyst 6500 series switch that runs CatOS release 6.3.2 or earlier with Supervisor Engine 2/Multilayer Switch Feature Card 2, can sometimes forward packets for some subnets to the wrong next-hop. This issue occurs due to stale prefix en...

Core issueVLAN-based SPAN (VSPAN) is used for the analysis of network traffic in one or more VLANs. You can configure VSPAN as ingress SPAN, egress SPAN, or both. For VSPAN sessions with both ingress and egress SPAN configured, the system operates as...