Cisco NME-16ES-1G User Guide - Page 24

Cisco Discovery Protocol, Switched Port Analyzer - p power

Page 24 highlights

Feature Overview 16- and 36-Port Ethernet Switch Module for Cisco 2600 Series, Cisco 3600 Series, and Cisco 3700 Series Cisco Discovery Protocol Cisco Discovery Protocol (CDP) is a protocol that runs over Layer 2 (the data link layer) on all Cisco routers, bridges, access servers, and switches. CDP allows network management applications to discover Cisco devices that are neighbors of already known devices, in particular, neighbors running lower-layer, transparent protocols. With CDP, network management applications can learn the device type and the SNMP agent address of neighboring devices. This feature enables applications to send SNMP queries to neighboring devices. CDP runs on all LAN and WAN media that support Subnetwork Access Protocol (SNAP). Each CDP-configured device sends periodic messages to a multicast address. Each device advertises at least one address at which it can receive SNMP messages. The advertisements also contain the time-to-live, or hold-time information, which indicates the length of time a receiving device should hold CDP information before discarding it. Switched Port Analyzer Switched Port Analyzer Session A Switched Port Analyzer (SPAN) session is an association of a destination interface with a set of source interfaces. You configure SPAN sessions using parameters that specify the type of network traffic to monitor. SPAN sessions allow you to monitor traffic on one or more interfaces and to send either ingress traffic, egress traffic, or both to one destination interface. You can configure one SPAN session with separate or overlapping sets of SPAN source interfaces or VLANs. Only switched interfaces can be configured as SPAN sources or destinations on the same network module. SPAN sessions do not interfere with the normal operation of the switch. You can enable or disable SPAN sessions with command-line interface (CLI) or SNMP commands. When enabled, a SPAN session might become active or inactive based on various events or actions, and this would be indicated by a syslog message. The show monitor session SPAN session number command displays the operational status of a SPAN session. A SPAN session remains inactive after system power-up until the destination interface is operational. Destination Interface A destination interface (also called a monitor interface) is a switched interface to which SPAN sends packets for analysis. You can have one SPAN destination interface. Once an interface becomes an active destination interface, incoming traffic is disabled. You cannot configure a SPAN destination interface to receive ingress traffic. The interface does not forward any traffic except that required for the SPAN session. An interface configured as a destination interface cannot be configured as a source interface. EtherChannel interfaces cannot be SPAN destination interfaces. Specifying a trunk interface as a SPAN destination interface stops trunking on the interface. Source Interface A source interface is an interface monitored for network traffic analysis. One or more source interfaces can be monitored in a single SPAN session with user-specified traffic types (ingress, egress, or both) applicable for all the source interfaces. You can configure source interfaces in any VLAN. You can configure EtherChannel as source interfaces, which means that all interfaces in the specified VLANs are source interfaces for the SPAN session. Cisco IOS Release 12.2(2)XT, 12.2(8)T, and 12.2(15)ZJ 24

  • 1
  • 2
  • 3
  • 4
  • 5
  • 6
  • 7
  • 8
  • 9
  • 10
  • 11
  • 12
  • 13
  • 14
  • 15
  • 16
  • 17
  • 18
  • 19
  • 20
  • 21
  • 22
  • 23
  • 24
  • 25
  • 26
  • 27
  • 28
  • 29
  • 30
  • 31
  • 32
  • 33
  • 34
  • 35
  • 36
  • 37
  • 38
  • 39
  • 40
  • 41
  • 42
  • 43
  • 44
  • 45
  • 46
  • 47
  • 48
  • 49
  • 50
  • 51
  • 52
  • 53
  • 54
  • 55
  • 56
  • 57
  • 58
  • 59
  • 60
  • 61
  • 62
  • 63
  • 64
  • 65
  • 66
  • 67
  • 68
  • 69
  • 70
  • 71
  • 72
  • 73
  • 74
  • 75
  • 76
  • 77
  • 78
  • 79
  • 80
  • 81
  • 82
  • 83
  • 84
  • 85
  • 86
  • 87
  • 88
  • 89
  • 90
  • 91
  • 92
  • 93
  • 94
  • 95
  • 96
  • 97
  • 98
  • 99
  • 100
  • 101
  • 102
  • 103
  • 104
  • 105
  • 106
  • 107
  • 108
  • 109
  • 110
  • 111
  • 112
  • 113
  • 114
  • 115
  • 116
  • 117
  • 118
  • 119
  • 120
  • 121
  • 122
  • 123
  • 124
  • 125
  • 126
  • 127
  • 128
  • 129
  • 130
  • 131
  • 132
  • 133
  • 134
  • 135
  • 136
  • 137
  • 138
  • 139
  • 140
  • 141
  • 142
  • 143
  • 144
  • 145
  • 146
  • 147
  • 148
  • 149
  • 150
  • 151
  • 152
  • 153
  • 154
  • 155
  • 156
  • 157
  • 158
  • 159
  • 160
  • 161
  • 162
  • 163
  • 164
  • 165
  • 166
  • 167
  • 168
  • 169
  • 170
  • 171
  • 172
  • 173
  • 174
  • 175
  • 176
  • 177
  • 178
  • 179
  • 180
  • 181
  • 182
  • 183
  • 184
  • 185
  • 186
  • 187
  • 188
  • 189
  • 190
  • 191
  • 192
  • 193
  • 194
  • 195
  • 196
  • 197
  • 198
  • 199
  • 200
  • 201
  • 202
  • 203
  • 204
  • 205
  • 206
  • 207
  • 208
  • 209
  • 210
  • 211
  • 212
  • 213
  • 214
  • 215
  • 216
  • 217
  • 218
  • 219
  • 220
  • 221
  • 222
  • 223
  • 224
  • 225
  • 226
  • 227
  • 228
  • 229
  • 230
  • 231
  • 232
  • 233
  • 234
  • 235
  • 236
  • 237
  • 238
  • 239
  • 240
  • 241
  • 242
  • 243
  • 244
  • 245
  • 246

16- and 36-Port Ethernet Switch Module for Cisco 2600 Series, Cisco 3600 Series, and Cisco 3700 Series
Feature Overview
24
Cisco IOS Release 12.2(2)XT, 12.2(8)T, and 12.2(15)ZJ
Cisco Discovery Protocol
Cisco Discovery Protocol (CDP) is a protocol that runs over Layer 2 (the data link layer) on all Cisco
routers, bridges, access servers, and switches. CDP allows network management applications to discover
Cisco devices that are neighbors of already known devices, in particular, neighbors running lower-layer,
transparent protocols. With CDP, network management applications can learn the device type and the
SNMP agent address of neighboring devices. This feature enables applications to send SNMP queries to
neighboring devices.
CDP runs on all LAN and WAN media that support Subnetwork Access Protocol (SNAP). Each
CDP-configured device sends periodic messages to a multicast address. Each device advertises at least
one address at which it can receive SNMP messages. The advertisements also contain the time-to-live,
or hold-time information, which indicates the length of time a receiving device should hold CDP
information before discarding it.
Switched Port Analyzer
Switched Port Analyzer Session
A Switched Port Analyzer (SPAN) session is an association of a destination interface with a set of source
interfaces. You configure SPAN sessions using parameters that specify the type of network traffic to
monitor. SPAN sessions allow you to monitor traffic on one or more interfaces and to send either ingress
traffic, egress traffic, or both to one destination interface. You can configure one SPAN session with
separate or overlapping sets of SPAN source interfaces or VLANs. Only switched interfaces can be
configured as SPAN sources or destinations on the same network module.
SPAN sessions do not interfere with the normal operation of the switch. You can enable or disable SPAN
sessions with command-line interface (CLI) or SNMP commands. When enabled, a SPAN session might
become active or inactive based on various events or actions, and this would be indicated by a syslog
message. The
show monitor session SPAN session number
command displays the operational status
of a SPAN session.
A SPAN session remains inactive after system power-up until the destination interface is operational.
Destination Interface
A destination interface (also called a monitor interface) is a switched interface to which SPAN sends
packets for analysis. You can have one SPAN destination interface. Once an interface becomes an active
destination interface, incoming traffic is disabled. You cannot configure a SPAN destination interface to
receive ingress traffic. The interface does not forward any traffic except that required for the SPAN
session.
An interface configured as a destination interface cannot be configured as a source interface.
EtherChannel interfaces cannot be SPAN destination interfaces.
Specifying a trunk interface as a SPAN destination interface stops trunking on the interface.
Source Interface
A source interface is an interface monitored for network traffic analysis. One or more source interfaces
can be monitored in a single SPAN session with user-specified traffic types (ingress, egress, or both)
applicable for all the source interfaces.
You can configure source interfaces in any VLAN. You can configure EtherChannel as source interfaces,
which means that all interfaces in the specified VLANs are source interfaces for the SPAN session.