Port A/B Setup > Frame Content

Selecting the Frame Content tab found in the Port A/B Setup folder will launch a screen as shown in Fig. 4.48.

Fig. 4.48 Frame Content screen found in Port A/B setup.

This screen contains setup of the Ethernet frame content transmitted by the CMA 3000. The exact layout is depending on the selected encapsu-lation and protocol headers.

Press the buttons in the uppermost row to change the composition of the transmitted frames. This will affect the available setups in the frame and the view below will expand or contract to reflect the layout of the frame composition selected.

The buttons are arranged in order, so the IP protocols are the uppermost layer and Ethernet the lowermost as depicted below compared to the OSI model (shown next page).

# OSI layer name Protocol

3 Network IP⁽¹⁾ / ICMP / ARP

2 Data Link IEEE 802.2 LLC Type 1/ LLC1 + SNAP⁽²⁾

VLAN⁽²⁾ Ethernet ll Frame⁽¹⁾

1 Physical e.g. 100BASE-TX

Referring to the table above:

(1)protocols can not be excluded, but content can be changed.

(2)protocols can be excluded and the content changed.

The Frame Content view shows each protocol layer with all the fields contained. Most fields are user-definable, but some are fixed, or changes dynamically based on e.g. frame size (which must be specified on the Traffic page).

The following softkeys are available: Stream*), ETH, MPLS*), EoMPLS*), VLAN, LLC1, SNAP, IPv4, IPv6, UDP, TCP and BERT*).

*) The ‘Stream’ and ‘BERT’ softkeys are only available when the Multist-ream option is installed. The ‘MPLS’ and ‘EoMPLS’ softkeys are only available when the MPLS option is installed.

Stream 1..8 The [Stream] softkey is used to select the stream to show. When press-ing this key a drop-down menu with a list from Stream 1 to Stream 8 is appearing. Selecting a stream here will show the setup frame content for this specific stream.

Port A and B Pressing the softkey [Port A] or [Port B] opens a drop-down menu from where Stream 1 to 8 can be selected. The stream selected will hereafter be copied to the Frame Content of the actual stream selected (indicated by the name of the [Stream] softkey.

The ‘Copy frame content from Port A’ and ‘Copy frame content from Port B’ softkey described above will only be available when the Ethernet Mul-tistream option is installed.

ETH It is possible to send unframed frames. In this mode the preamble, the BERT pattern and the optional sequence number are send on the line.

The ‘ETH’ softkey and therefore the BERT is only available in ‘Stream1’.

Ethernet The Ethernet (MAC) header contains MAC addresses and Ethertype.

The type is automatically defined based on the above protocol layer.

Fig. 4.49 The Ethernet field.

4.8 Interface > Ethernet

The Destination MAC address can either be specified manually, or be de-cided based on an ARP lookup, to enable ARP press the [ARP] softkey to the right of the Destination MAC address field. The ‘Broadcast’ control is used to set the ratio between Unicast and Broadcast frames transmit-ting.

Fig. 4.50 The [ ! ] softkey appears when pressing the [ARP] softkey.

When ARP is selected a new softkey will appear next to the ARP key.

This [ ! ] softkey is an ‘instant ARP’ key that when pressed will perform an ARP lookup immediately, instead of waiting until the transmitter starts.

Source MAC address can be specified manually but the instrument comes with a default unique MAC address for each port.

If the Use default field is selected the source MAC address will not be changed when settings are loaded.

Encapsulation affects the Ping and RFC2544/Router Latency test, i.e.

Ping replies will only be sent if the Ping request contains the same en-capsulation as the one selected.

VLAN affects the Ping and RFC2544/Router Latency test, i.e. when VLAN is enabled, only frames with VLAN tag will be accepted, further-more Ping replies will only be sent if the Ping request contains the same VLAN ID as the one selected.

MPLS

Multi Protocol Label Switching (MPLS) encapsulation. When the

‘MPLS’ option is installed, up to eight levels of MPLS fields can be insert-ed in the frame. The number of MPLS fields is selectinsert-ed through the Level count drop-down menu, and each level is set up individually.

Fig. 4.51 The MPLS field

Pressing the Label field launches a setup menu from which it is possible to setup a denoting of the MPLS.

Pressing the EXP field launches a setup menu from which it is possible to setup the 3 bit value EXP (Experimental - used in MPLS to support dif-ferentiated services (priority)).

Pressing the TTL field launches a setup menu from which it is possible to setup the 8 bit value TTL (Time To Live).

EoMPLS

Ethernet over Multi Protocol Label Switching (EoMPLS). When the

‘MPLS’ option is installed, an embedded Ethernet field can be inserted in the frame. This requires that MPLS is active.

When EoMPLS is active the ARP button will be moved away from the pri-mary Ethernet field.

Fig. 4.52 The EoMPLS field

Enabling the Auto increment sequence number field makes the se-quence number in the rfc4448 control word increment automatically in-stead of being fixed to zero.

The remaining fields are described in the Ethernet part of this section.

VLAN Virtual LAN (VLAN) is used to create independent logical networks within a physical network. When enabled, it adds a 16 bit IEEE 802.1Q field and a 16 bit Ethertype field to the header. The 802.1Q is separated into 3 parts.

Fig. 4.53 The VLAN field.

Pressing the VID (VLAN ID) field launches a setup menu from which it is possible to setup a denoting of the virtual LAN.

Enabling the CFI field sets a 1-bit flag denoting whether MAC addresses inside the frame are in canonical format.

4.8 Interface > Ethernet

Pressing the Priority field launches a setup menu from which it is possible to setup the priority level of each frame.

When the ‘stacked VLAN’ option is installed, up to eight levels of VLAN can be inserted in the frame.

The number of VLAN fields is selected through the Level count drop-down menu, and each level is set up individually.

Fig. 4.54 The stacked VLAN field

When the VLAN level count is 2. The two VLAN levels will be designated S-VLAN and VLAN. S-VLAN is short for Service provider VLAN and C-VLAN is short for Customer C-VLAN.

Fig. 4.55 The stacked VLAN field when the level count is 2

LLC Logical Link Control (LLC). The DSAP, SSAP and Control fields are set automatically based on the upper protocol layer.

SNAP SubNetwork Access Protocol (SNAP). The Protocol ID is fixed to 0, and the Ethertype field is depending on the upper protocol layer.

SNAP’ is not possible without ‘LLC1’, and ‘IPv4’ and ‘IPv6’ are substi-tutes.

IPv4 Internet Protocol version 4 (IPv4). When changing the DSCP/TOS (Dif-ferentiated Service Code Point/Type of Service) field it is possible to de-fine some handling characteristics of the datagram, originally dede-fined in RFC791. Other uses of the DSCP/TOS field are VoIP, DiffServ and ECN.

Fig. 4.56 The IPv4 field.

The Identifier field is mainly used for uniquely identifying fragments of an IP datagram. When the Auto increment is selected, the Identifier will be different for each sent frame.

Flags

• MF (More Fragments) – When a packet is fragmented all fragments have the MF flag set except the last fragment.

• DF (Don't Fragment) – If the DF flag is set and fragmentation is re-quired to route the packet then the packet will be dropped.

• RES (Reserved) – Must be zero.

TTL (Time To Live) defines the number of 'hops' a datagram can do be-fore it no longer is forwarded.

The Protocol field defines the upper/next layer protocol encapsulated in the IP datagram. Typical values in hex are: 1 = ICMP, 6 = TCP etc.

Source IP address and Destination IP address can be entered by the for-mat: 255.255.255.255.

When Multistream traffic is sent from one port to another make sure that the source address on one port is the same as the destination address on the other port for each of the active streams. This applies if the two ports are in one instrument or in two different instruments.

Pressing the [DHCP] softkey located next to the source IP address line will enable the Dynamic Host Configuration Protocol function. When it is active the virtual LED will turn from black to red, as shown in Fig. 4.56.

Pressing the [Setup] softkey next to the virtual LED will open the DHCP Setup screen shown in Fig. 4.57.

4.8 Interface > Ethernet

Fig. 4.57 DHCP setup screen.

A tick in the Renew lease when link is re-established box enables the function that automatically renew the lease when the link is reestab-lished.

A tick in the Get gateway setup through DHCP box enables the function that automatically assign the gateway.

A tick in the Get DNS servers through DHCP box enables the function that automatically assign the DNS server.

Pressing the Primary DNS server and the Secondary DNS server field re-spectively allows you to define these IPv4 addresses for the specific stream.

When allocating IP addresses using DHCP, it is ‘leased’ for a certain pe-riod of time defined by the network. The time when the lease expires is indicated as current release expire time.

Pressing the [Renew now] softkey will renew the allocation of the IP ad-dress.

Pressing the [Close] softkey closes the setup.

Pressing the [DNS] softkey located next to the Destination IP address field launches the Keyboard pop-up for insertion of a name for the desti-nation.

When pressing the [Gateway] softkey a popup will be shown, where De-fault Gateway and Network mask can be specified. When Gateway is en-abled and the gateway/source address mask falls outside the network mask, an ARP lookup for the gateway IP address will be made. The re-sulting MAC address is used as destination. Gateway is usually used with ARP enabled as well.

IPv6 Internet Protocol version 6 (IPv6). Traffic Class is similar to IPv4´s TOS field and used for the class and priority, one definition is located in RFC 2474.

Fig. 4.58 The IPv6 field.

Flow Label indicates that the datagram belongs to a specific sequence of traffic between a source and destination. The default value is 0.

Next Header indicates the upper/next layer of IPv6. The field corre-sponds to the Protocol field in IPv4.

Hop Limit defines the number of 'hops' a datagram can do before it no longer is forwarded.

Source IP address and Destination IP address can be entered by the for-mat xxxx:xxxx:xxxx:xxxx:xxxx:xxxx:xxxx:xxxx (32 Hex values).

UDP User Datagram Protocol (UDP) is a core protocol of the Internet protocol suite. The UDP provides a minimal and simple interface between a net-work layer below and a session layer or application above. This protocol does not guarantee reliable and in-order delivery from sender to receiver.

Fig. 4.59 The UDP field.

Source port identifies the sending port and should be assumed to be the port to reply to if needed. If not used, then it should be zero

Destination port identifies the destination port and is required.

Optionally, the Checksum may be forced to zero, by selecting the Null field.

4.8 Interface > Ethernet

TCP Transmission Control Protocol (TCP) is a core protocol of the Internet protocol suite. It is the intermediate layer between the Internet Protocol below it and the application above it. This protocol guarantees reliable and in-order delivery from sender to receiver.

The CMA 3000 supports sending frames that resemble TCP frames, but the traffic transmitted will not constitute a real TCP stream, as no hand-shake is performed.

Fig. 4.60 The TCP field.

By enabling the Automatic TCP connect it is possible to force the trans-mitter to establish a TCP connection before the actual traffic frames are send. This makes it possible to pass a firewall/nat router from the inner side.

By enabling the Listen Mode the transmitter will await an external TCP connection before the actual traffic frames are send. This makes it pos-sible to pass a firewall/nat router from the outher side (Remark: you must have something establishing the TCP connection from the inner side e.g.

CMA 3000). In this mode the peers MAC, IP, and Port is taken from the incomming TCP connection.

Source port identifies the sending port.

Destination port identifies the receiving port.

Sequence number (if the SYN flag is present) this is the initial sequence number and the first data byte is the sequence number plus 1 (if the SYN flag is not present) then the first data byte is the sequence number. The Auto increment may be selected in order for the Sequence number to fol-low the number of data bytes send (Remark: the first data byte will be number zero in this mode, and not the number entered into the Sequence number field).

Ack number if the ACK flag is set then the value of this field is the se-quence number that the sender of the acknowledgment expects next.

Data offset specifies the size of the TCP header in 32-bit words. The Min.

is 5 words and the Max. is 15 words thus giving the Min. size of 20 bytes and Max. of 60 bytes. This field gets its name from the fact that it is also the offset from the start of the TCP packet to the data.

Reserved for future use and should be set to zero.

Flags (Control bits) – contains 8 bit flags. The flags may be programmed individually, however when Automatic TCP connect is enabled, most of the flags are controlled by the TCP state engine.

Window the number of bytes that may be received on the receiving side before being halted from sliding any further and receiving any more bytes as a result of a packet at the beginning of the sliding window not having been acknowledged or received. Starts at acknowledgement field.

Checksum The 16-bit checksum field is used for error-checking of the header and data.

Urgent pointer if the URG flag is set, then this 16-bit field is an offset from the sequence number indicating the last urgent data byte.

BERT Press this softkey to enable the test of the received BERT.

The ‘BERT’ softkey is only available in ‘Stream1’.

To enable BER testing on the Ethernet interface the payload must be set to one of the BERT modes available.

Payload At the bottom of the Frame Content page it is possible to set the pattern of the Payload of the transmitted frames. E.g. the Pattern and selecting Multistream Frame Loss.

Follow A/stream 1..8

Feature for Port B setup only. Setting a check in the Follow A box inverts the port A addresses and inserts them in the address fields of port B.

4.8 Interface > Ethernet