ES-IS ISH (esis_ish)
- Layer: L3 (network)
- Header: variable length
- Notes: CLNP / ES-IS (P2), OSI encapsulation (P2)
Reached from
| Lower layer | Selector | Value |
|---|---|---|
llc | First 8 bits of the payload when dsap = 254 (0xfe) | 130 (0x82) |
ppp | First 8 bits of the payload when protocol = 35 (0x0023) | 130 (0x82) |
esis | pdu_type | 4 (re-decodes this layer) |
Fields
| Field | Type | Default | Auto | Description |
|---|---|---|---|---|
nlpid | enum(8) | 130 (esis) | Network layer protocol identifier (0x82 = ES-IS). | |
length_indicator | uint(8) | Length of the header in octets | Length of the PDU in octets (Auto). | |
version | uint(8) | 1 | Version / protocol ID extension (1). | |
reserved | uint(8) | 0 | ||
reserved_type | uint(3) | 0 | ||
pdu_type | enum(5) | 4 (ish) | PDU type: 2 ESH (end system hello), 4 ISH (intermediate system hello), 6 RD (redirect). | |
holding_time | uint(16) | 30 | Holding time in seconds. | |
checksum | uint(16) | Fletcher checksum over the header | ISO 8473 Fletcher checksum of the PDU (Auto). 0 = checksum not used. | |
net | nsap | 49.0001.0000.0000.0001.00 | Network entity title of the intermediate system (redirect: empty when the next hop is an end system). | |
options | tlv — up to offset length_indicator of the group | [] | Options (8-bit code / 8-bit length) up to the length indicator: security, QoS maintenance, priority, address mask, SNPA mask, suggested ES configuration timer. |
nlpid
| Value | Name |
|---|---|
| 130 (0x82) | esis |
pdu_type
| Value | Name |
|---|---|
| 2 | esh |
| 4 | ish |
| 6 | rd |
options
- Type 8 bits, length 8 bits.
- The length counts the value only.
- Unknown types are kept as raw value octets.
| Type | Name | Value fields | Description |
|---|---|---|---|
| 197 (0xc5) | security | value | |
| 195 (0xc3) | qos_maintenance | value | |
| 205 (0xcd) | priority | value | |
| 225 (0xe1) | address_mask | mask | |
| 226 (0xe2) | snpa_mask | mask | |
| 198 (0xc6) | es_configuration_timer | seconds |
options › security
| Field | Type | Default | Auto | Description |
|---|---|---|---|---|
value | bytes — rest of the PDU |
options › qos_maintenance
| Field | Type | Default | Auto | Description |
|---|---|---|---|---|
value | bytes — rest of the PDU |
options › priority
| Field | Type | Default | Auto | Description |
|---|---|---|---|---|
value | uint(8) |
options › address_mask
| Field | Type | Default | Auto | Description |
|---|---|---|---|---|
mask | bytes — rest of the PDU |
options › snpa_mask
| Field | Type | Default | Auto | Description |
|---|---|---|---|---|
mask | bytes — rest of the PDU |
options › es_configuration_timer
| Field | Type | Default | Auto | Description |
|---|---|---|---|---|
seconds | uint(16) |
Sample templates
- esis-ish —
templates/protocols/routing/esis-ish.wpg.yaml