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    Measuring Performance

    The performance of a service provider’s network is usually defined as how well it can support services, and is measured with metrics such as delay and utilization. We suggest that you monitor the following performance metrics using applications such as InfoVista Service Performance Management or Concord Network Health (see Table 1).

    Table 1: Performance Metrics

    Metric:

    Average delay

    Description

    Average round-trip time (in milliseconds) between two measurement points.

    MIB name

    DISMAN-PING-MIB (RFC 2925)

    Variable name

    pingResultsAverageRtt

    Variable OID

    pingResultsEntry.6

    Frequency (mins)

    15 (or depending upon ping test frequency)

    Allowable range

    To be baselined

    Managed objects

    Each measured path in the network

    Metric:

    Interface utilization

    Description

    Utilization percentage of a logical connection.

    MIB name

    IF-MIB

    Variable name

    (ifInOctets & ifOutOctets) * 8 / ifSpeed

    Variable OID

    ifTable entries

    Frequency (mins)

    60

    Allowable range

    To be baselined

    Managed objects

    All operational interfaces in the network

    Metric:

    Disk utilization

    Description

    Utilization of disk space within the Juniper Networks router

    MIB name

    HOST-RESOURCES-MIB (RFC 2790)

    Variable name

    hrStorageSizehrStorageUsed

    Variable OID

    hrStorageEntry.5 – hrStorageEntry.6

    Frequency (mins)

    1440

    Allowable range

    To be baselined

    Managed objects

    All Routing Engine hard disks

    Metric:

    Memory utilization

    Description

    Utilization of memory on the Routing Engine and FPC.

    MIB name

    JUNIPER-MIB (Juniper Networks enterprise Chassis MIB)

    Variable name

    jnxOperatingHeap

    Variable OID

    Table for each component

    Frequency (mins)

    60

    Allowable range

    To be baselined

    Managed objects

    All Juniper Networks routers

    Metric:

    CPU load

    Description

    Average utilization over the past minute of a CPU.

    MIB name

    JUNIPER-MIB (Juniper Networks enterprise Chassis MIB)

    Variable name

    jnxOperatingCPU

    Variable OID

    Table for each component

    Frequency (mins)

    60

    Allowable range

    To be baselined

    Managed objects

    All Juniper Networks routers

    Metric:

    LSP utilization

    Description

    Utilization of the MPLS label-switched path.

    MIB name

    MPLS-MIB

    Variable name

    mplsPathBandwidth / (mplsLspOctets * 8)

    Variable OID

    mplsLspEntry.21 and mplsLspEntry.3

    Frequency (mins)

    60

    Allowable range

    To be baselined

    Managed objects

    All label-switched paths in the network

    Metric:

    Output queue size

    Description

    Size, in packets, of each output queue per forwarding class, per interface.

    MIB name

    JUNIPER-COS-MIB

    Variable name

    jnxCosIfqQedPkts

    Variable OID

    jnxCosIfqStatsEntry.3

    Frequency (mins)

    60

    Allowable range

    To be baselined

    Managed objects

    For each forwarding class per interface in the network, once CoS is enabled.

    This section includes the following topics:

    Measuring Class of Service

    You can use class-of-service (CoS) mechanisms to regulate how certain classes of packets are handled within your network during times of peak congestion. Typically you must perform the following steps when implementing a CoS mechanism:

    • Identify the type of packets that is applied to this class. For example, include all customer traffic from a specific ingress edge interface within one class, or include all packets of a particular protocol such as voice over IP (VoIP).
    • Identify the required deterministic behavior for each class. For example, if VoIP is important, give VoIP traffic the highest priority during times of network congestion. Conversely, you can downgrade the importance of Web traffic during congestion, as it may not impact customers too much.

    With this information, you can configure mechanisms at the network ingress to monitor, mark, and police traffic classes. Marked traffic can then be handled in a more deterministic way at egress interfaces, typically by applying different queuing mechanisms for each class during times of network congestion. You can collect information from the network to provide customers with reports showing how the network is behaving during times of congestion. (See Figure 1.)

    Figure 1: Network Behavior During Congestion

    Network Behavior During Congestion

    To generate these reports, routers must provide the following information:

    • Submitted traffic—Amount of traffic received per class.
    • Delivered traffic—Amount of traffic transmitted per class.
    • Dropped traffic—Amount of traffic dropped because of CoS limits.

    The following section outlines how this information is provided by Juniper Networks routers.

    Inbound Firewall Filter Counters per Class

    Firewall filter counters are a very flexible mechanism you can use to match and count inbound traffic per class, per interface. For example:

    firewall {
    filter f1 {
    term t1 {
    from {
    dscp af11;
    }
    then {
    # Assured forwarding class 1 drop profile 1 count inbound-af11;
    accept;
    }
    }
    }
    }

    For example, Table 2 shows additional filters used to match the other classes.

    Table 2: Inbound Traffic Per Class

    DSCP Value

    Firewall Match Condition

    Description

    10

    af11

    Assured forwarding class 1 drop profile 1

    12

    af12

    Assured forwarding class 1 drop profile 2

    18

    af21

    Best effort class 2 drop profile 1

    20

    af22

    Best effort class 2 drop profile 2

    26

    af31

    Best effort class 3 drop profile 1

    Any packet with a CoS DiffServ code point (DSCP) conforming to RFC 2474 can be counted in this way. The Juniper Networks enterprise-specific Firewall Filter MIB presents the counter information in the variables shown in Table 3.

    Table 3: Inbound Counters

    Indicator Name

    Inbound Counters

    MIB

    jnxFirewalls

    Table

    jnxFirewallCounterTable

    Index

    jnxFWFilter.jnxFWCounter

    Variables

    jnxFWCounterPacketCount

    jnxFWCounterByteCount

    Description

    Number of bytes being counted pertaining to the specified firewall filter counter

    SNMP version

    SNMPv2

    This information can be collected by any SNMP management application that supports SNMPv2. Products from vendors such as Concord Communications, Inc., and InfoVista, Inc., provide support for the Juniper Networks Firewall MIB with their native Juniper Networks device drivers.

    Monitoring Output Bytes per Queue

    You can use the Juniper Networks enterprise ATM CoS MIB to monitor outbound traffic, per virtual circuit forwarding class, per interface. (See Table 4.)

    Table 4: Outbound Counters for ATM Interfaces

    Indicator Name

    Outbound Counters

    MIB

    JUNIPER-ATM-COS-MIB

    Variable

    jnxCosAtmVcQstatsOutBytes

    Index

    ifIndex.atmVclVpi.atmVclVci.jnxCosFcId

    Description

    Number of bytes belonging to the specified forwarding class that were transmitted on the specified virtual circuit.

    SNMP version

    SNMPv2

    Non-ATM interface counters are provided by the Juniper Networks enterprise-specific CoS MIB, which provides information shown in Table 5.

    Table 5: Outbound Counters for Non-ATM Interfaces

    Indicator Name

    Outbound Counters

    MIB

    JUNIPER-COS-MIB

    Table

    jnxCosIfqStatsTable

    Index

    jnxCosIfqIfIndex.jnxCosIfqFc

    Variables

    jnxCosIfqTxedBytes

    jnxCosIfqTxedPkts

    Description

    Number of transmitted bytes or packets per interface per forwarding class

    SNMP version

    SNMPv2

    Dropped Traffic

    You can calculate the amount of dropped traffic by subtracting the outbound traffic from the incoming traffic:

    Dropped = Inbound Counter – Outbound Counter

    You can also select counters from the CoS MIB, as shown in Table 6.

    Table 6: Dropped Traffic Counters

    Indicator Name

    Dropped Traffic

    MIB

    JUNIPER-COS-MIB

    Table

    jnxCosIfqStatsTable

    Index

    jnxCosIfqIfIndex.jnxCosIfqFc

    Variables

    jnxCosIfqTailDropPkts

    jnxCosIfqTotalRedDropPkts

    Description

    The number of tail-dropped or RED-dropped packets per interface per forwarding class

    SNMP version

    SNMPv2

    Modified: 2017-08-31