Troubleshooting guide

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3.5.6 Actions to be taken for PoE problems ....................................................................... 43
3.5.7 Communication failures when link aggregation is used ............................................ 44
3.6 Layer 2 network communication failures ............................................................................. 46
3.6.1 Layer 2 communication by VLANs is not possible ................................................... 46
3.6.2 Failures occurring when the Spanning Tree functionality is used ............................. 49
3.6.3 Failures occurring when the Ring Protocol functionality is used .............................. 50
3.6.4 Multicast forwarding by IGMP snooping is not possible .......................................... 52
3.6.5 Multicast forwarding by MLD snooping is not possible ........................................... 55
3.7 IPv4 network communication failures .................................................................................. 59
3.7.1 Communication is not possible or is disconnected .................................................... 59
3.7.2 IP addresses cannot be assigned by the DHCP functionality .................................... 63
3.7.3 Dynamic DNS link does not work in the DHCP functionality .................................. 69
3.8 IPv4 unicast routing communication failures ....................................................................... 72
3.8.1 No RIP routing information exists ............................................................................. 72
3.8.2 No OSPF routing information exists ......................................................................... 72
3.8.3 No BGP4 routing information exists ......................................................................... 73
3.8.4 IPv4 routing information cannot be found in VRF .................................................... 74
3.9 Communication failures in the IPv4 multicast routing functionality .................................... 75
3.9.1 Communication is not possible on the IPv4 PIM-SM networks ............................... 75
3.9.2 Multicast data is forwarded twice in the IPv4 PIM-SM network .............................. 79
3.9.3 Communication is not possible on the IPv4 PIM-SSM networks ............................. 79
3.9.4 Multicast data is forwarded twice in the IPv4 PIM-SSM network ............................ 82
3.9.5 IPv4 multicast communication problems in VRF ..................................................... 83
3.9.6 Problems that occur during IPv4 multicast communication in the extranet .............. 84
3.9.7 Communication is not possible on the IPv4 PIM-DM networks ............................... 84
3.9.8 Multicast data is forwarded twice in the IPv4 PIM-DM network ............................. 87
3.10 IPv6 network communication failures ................................................................................ 88
3.10.1 Communication is not possible or is disconnected .................................................. 88
3.10.2 IPv6 DHCP relay communication problems ........................................................... 91
3.10.3 Troubleshooting IPv6 DHCP server problems ........................................................ 94
3.11 IPv6 unicast routing communication failures ..................................................................... 99
3.11.1 RIPng routing information cannot be found ............................................................ 99
3.11.2 OSPFv3 routing information cannot be found ......................................................... 99
3.11.3 No BGP4+ routing information exists ................................................................... 100
3.11.4 No IPv6 routing information exists in the VRF ..................................................... 101
3.12 Communication failures in the IPv6 multicast routing functionality ................................ 102
3.12.1 Communication is not possible on the IPv6 PIM-SM networks ........................... 102
3.12.2 Multicast data is forwarded twice in the IPv6 PIM-SM network .......................... 106
3.12.3 Communication is not possible on the IPv6 PIM-SSM networks ......................... 106
3.12.4 Multicast data is forwarded twice in the IPv6 PIM-SSM network ........................ 109
3.12.5 IPv6 multicast communication problems in VRF ................................................. 110
3.12.6 IPv6 multicast communication problems in an extranet ........................................ 110
3.13 Layer 2 authentication communication failures ................................................................ 112
3.13.1 Communication failures occurring when IEEE 802.1X is used ............................ 112
3.13.2 Communication failures occurring when Web authentication is used ................... 115
3.13.3 Communication failures occurring when MAC-based authentication is used ...... 120
3.13.4 Communication failures occurring when an authentication VLAN is used .......... 123
3.14 Communication failures in the high-reliability functionality ........................................... 127
3.14.1 GSRP communication failures .............................................................................. 127
3.14.2 Communication is not possible with the VRRP configuration of IPv4 networks . 129
3.14.3 Communication is not possible with the VRRP configuration of IPv6 networks . 131
3.14.4 Communication is not possible with uplink redundancy ....................................... 134
3.15 SNMP communication failures ......................................................................................... 136
3.15.1 MIBs cannot be obtained from the SNMP manager .............................................. 136
3.15.2 Traps cannot be received by the SNMP manager .................................................. 136
3.16 Troubleshooting the sFlow statistics (flow statistics) functionality .................................. 138